Email Verification Tool to Prevent 5.7.13 DMARC Violations in HubSpot

Why Does HubSpot Keep Rejecting Emails with Error 5.7.13?

You just sent a batch of emails through HubSpot, and you get a bounce: 5.7.13 from Microsoft’s SMTP server. The message says your email failed DMARC alignment — even though the addresses look valid. You’re not alone. This error shows up regularly when trying to send to domains that either don’t have DMARC policies or don’t align with your sending domain.

Here’s the reality: even a perfectly formatted email can be rejected if the recipient’s domain blocks messages from unaligned senders. The problem isn’t the email itself — it’s the domain’s security posture. This is where an email verification tool to prevent 5.7.13 DMARC violations in HubSpot becomes essential. It doesn’t just check if an address exists — it tests whether that domain authorizes your sending domain to deliver there.

Key takeaways

• DMARC violation errors like 5.7.13 occur when your sending domain doesn’t align with the domain of the email address you're sending to.
• Even valid email addresses can trigger 5.7.13 if the recipient domain enforces strict DMARC policies or lacks proper authentication records.
• An email verification tool that checks DMARC alignment and domain authentication reduces bounce rates and prevents deliverability issues in HubSpot.

Can Email Verification Fix 5.7.13 DMARC Violations in HubSpot?

Not directly. An email verification tool doesn’t fix DMARC alignment issues—those are about DNS records and policy enforcement. But it can help prevent 5.7.13 errors in HubSpot by catching invalid or high-risk addresses before they’re sent. If you're sending to domains with poor authentication or known delivery problems, your messages are likely to be blocked with a 5.7.13 error. Verification doesn’t fix alignment, but it stops you from sending to those domains in the first place.

Why 5.7.13 Happens in HubSpot

When HubSpot sends an email, the recipient’s mail server checks DMARC policies. If the sending domain doesn’t align with SPF or DKIM (or if the envelope sender fails DMARC), you get a 5.7.13 error. This is often flagged for emails sent from third-party services, especially if the sender’s domain isn't properly authenticated. The error isn’t about the recipient’s address—it’s about how the sending domain is validated.

But here’s the catch: if you’re sending to domains that are misconfigured or don’t enforce DMARC at all, you’re still likely to trigger a 5.7.13 rejection, even if your email is legitimate. That’s why cleaning your list is a key strategy. You’re not fixing the sender’s domain—just avoiding sending to domains where alignment fails.

How Verification Reduces Risk

By filtering out addresses from domains with weak or broken authentication, you lower the odds that your HubSpot campaigns get bounced with 5.7.13. A good email verification tool checks for syntax, domain existence, and mailbox reachability. It also flags domains known for high bounce rates or poor delivery reputation—those are often the ones with DMARC misalignment.

Let’s say you have a list with 10% of addresses from domains that don’t enforce DMARC or have been associated with sending issues. Sending to those domains increases your risk of 5.7.13, even if your own setup is correct. Removing them before sending reduces that exposure.

Verification doesn’t change your DNS records, but it helps you avoid sending to risky domains. That’s how it prevents 5.7.13 at scale—by making your list safer before it ever touches HubSpot.

A real-time verification API or bulk list cleaning service can catch these risks early. With 98.9% accuracy, tools like bulk email list cleaning help you send only to valid, addressable inboxes—reducing bounces, improving sender reputation, and indirectly lowering DMARC-related rejection flags.

What’s the Real Problem Behind 5.7.13 Errors?

5.7.13 DMARC failures happen when your email’s authentication fails because the sending domain doesn’t match the From address, or the sending IP isn’t authorized. Even if an email address is perfectly valid, mismatched domains or unverified IPs will get blocked by receiving servers that enforce strict DMARC policies.

Why Your Emails Are Rejected, Even When Addresses Are Valid

DMARC checks two things: whether SPF and DKIM pass, and whether the domains in the From header and envelope sender align. If they don’t—like sending from [email protected] but using a different domain in the SMTP envelope—the email gets rejected with a 5.7.13 error. This happens even if the mailbox exists and the syntax is correct.

Let’s say you’re using a third-party platform like HubSpot to send emails through a subdomain like mail.yourcompany.com. If the From address in your email says [email protected] but your email wasn’t authorized to send from that domain, DMARC will flag it. The same goes if the sending IP isn’t in SPF’s allowed list. The receiving server sees the mismatch and blocks the message.

How Dirty Lists Trigger DMARC Failures

You might assume that fixing syntax errors is enough. But if your list includes email addresses from domains that don’t match your sending domain—or that lack proper SPF/DKIM records—you’re setting up a DMARC failure, even before the message leaves your server.

For example, a list of contacts from @gmail.com used to send transactional messages from @yourcompany.com creates an automatic alignment failure. The receiving mail server sees the From domain and the sending domain as separate, and blocks it. This is common when you import outdated or acquired lists without cleaning them first. The result? High bounce rates, poor deliverability, and damage to sender reputation.

Even a few bad records in a large list can cause systemic issues. If your sender IP is repeatedly involved in DMARC failures, ISPs may rate-limit or block your domain entirely.

Think of it like sending a letter from the wrong post office: the address is correct, but the envelope doesn’t match the sender’s ID. That’s what happens with unverified or misaligned domains in bulk sends.

Proactive verification catches these issues early. You can spot invalid, catch-all, or mismatched domains before sending—so your messages align with DMARC requirements.

Clean your list in bulk before sending, and ensure every domain aligns with your sending domain.

How Email Verification Prevents 5.7.13 Before It Happens

You can prevent 5.7.13 DMARC-related bounces in HubSpot by using an email verification tool that checks domains in real time, identifies those blocking mail due to DMARC or SPF misalignment, and removes them from your list before you send. This stops rejected messages before they leave your server, reducing bounce rates and protecting sender reputation.

Verifying Addresses at the Protocol Level

When you send mail via HubSpot, the system relies on the recipient’s mail server to accept or reject the message. A true email verification tool doesn’t just check syntax — it performs a real SMTP handshake, testing whether the address exists, the domain is routable, and the server responds without error. This process mirrors what happens during actual delivery, giving you reliable insight before you send.

During this check, the tool monitors for error codes like 5.7.13, which specifically point to policy violations — most often DMARC or SPF misalignment. If a domain consistently returns 5.7.13, it means the server is rejecting messages not because the address doesn’t exist, but because it doesn’t meet the sender’s authentication policy. These are not temporary failures; they’re intentional rejections.

Blocking Problem Domains Before They Cause Damage

By catching these signals early, a verification tool flags domains that are known to reject mail based on policy, not delivery issues. You can then remove those addresses from your list entirely. This prevents you from sending to accounts that will not receive your message, which directly reduces hard bounces and improves inbox placement over time.

DMARC is an industry-standard email authentication mechanism, and servers that enforce it do so strictly. According to the DMARC specification (RFC 7483), receivers are allowed to reject mail when authentication fails. Repeated 5.7.13 errors signal that your sending domain doesn't align with the recipient’s policies — even if your mail is technically valid.

Let’s say you’re sending to a domain where the SPF record is too restrictive or the DMARC policy is set to reject. If your sender isn’t properly aligned, the server will reject the email. But if you run the address through a verification tool first, you’ll see that it fails validation — not because it’s fake, but because it’s intentionally blocked. You won’t waste bandwidth sending to a known dead end.

With tools like Email List Validation, you can clean your entire list in bulk, or integrate verification directly into your HubSpot workflows using the real-time API. Either way, you catch 5.7.13 risks before they impact your deliverability. The result? Fewer bounces, better sender reputation, and mail that lands in inboxes — not outbox rejects.

Step-by-Step: Clean Your HubSpot List to Prevent 5.7.13 Errors

You can prevent 5.7.13 DMARC violations in HubSpot by cleaning your email list before sending. Export your contact list with email and domain data, then verify each address using a trusted email verification tool. Filter out domains that return 'rejected' or '5.7.13' errors, and remove or flag those contacts. Re-import only validated records to avoid delivery failures and maintain sender reputation. This simple process stops bounces and protects deliverability.

How to Identify and Handle 5.7.13 Errors

DMARC error 5.7.13 means the receiving server rejected your message due to misaligned authentication. It’s not about the email address—it’s about the domain’s policies. Let’s clean your HubSpot list to prevent this.

1. Export your HubSpot contact list with the Email and Domain columns. Include any relevant metadata like last activity or lead source. This ensures you can trace cleaned records back to their origin.
2. Upload the list to Email List Validation via the Web interface or real-time API. The tool validates every address at scale with 98.9% accuracy, checking syntax, domain existence, and mail server responses. Use bulk verification for large datasets.
3. Review the results and filter for entries marked as 'rejected' or where the delivery check returns a 5.7.13 error. These domains explicitly reject your messages due to DMARC, SPF, or DKIM policy mismatches.
4. Remove or flag records with 5.7.13 domains. Don’t send to them. If a domain appears frequently, assess whether it’s on a blocklist or intentionally not accepting mail. Some domains, like admin@ or support@, are often used for non-receipt purposes and don’t expect inbound messages.
5. Re-import the cleansed list into HubSpot. Only verified, active addresses should be in your campaign send list. This reduces bounce rates significantly and avoids penalizing your sender reputation.

DMARC enforcement is increasing across major providers. According to RFC 7489, organizations should enforce strict alignment to reduce spoofing and phishing. Ignoring 5.7.13 errors risks being blocked entirely. Regular list hygiene is part of that defense.

You don’t need to verify everything on every campaign, but if you're seeing recurring 5.7.13 errors in HubSpot reports, you’re likely sending to domains that don’t accept your mail—either due to policy or infrastructure. Prevention is more efficient than fix.

What Verdicts Does Email List Validation Return for DMARC Risk?

You get five verdicts: Valid (real and accepting mail), Invalid (nonexistent or permanently rejected), Catch-all (accepts all emails, high spam risk), Risky (shows transient errors like 5.7.13, often due to DMARC alignment or policy issues), and Dispos (disposable email domain). These verdicts help you identify and remove addresses that will trigger DMARC rejections in HubSpot or other ESPs.

Each Verdict Explains the Mail Flow Risk

Let's break down what each result means in practice:

DMARC violations in HubSpot often stem from sending to accounts where authentication policies conflict with sending domains. The Risky verdict is your early signal: if your messages are rejecting with errors like 5.7.13, the recipient’s DMARC policy is likely rejecting your mail — not because the address is fake, but because the authentication path is broken.

For context, DMARC enforcement is an industry-standard practice. The Email Domain Monitor reports that over 80% of major email providers now enforce DMARC policies, making alignment crucial.

Why DMARC-Friendly Domains Are Still at Risk in Mass Campaigns

Even with strong DMARC policies, emails to corporate domains—especially in finance, healthcare, and government—can fail if the sending IP isn’t explicitly allowed. DMARC doesn’t just reject messages based on sender authenticity; it relies on strict alignment, and if HubSpot’s IP isn’t in the domain’s allowlist, delivery fails with code 5.7.13, regardless of how valid the email address appears.

DMARC Isn’t Just About Authentication—It’s About Trust

DMARC policies are designed to block spoofed emails by verifying SPF and DKIM alignment. But this doesn’t mean every authenticated send is approved. Many organizations use DMARC in "reject" mode, which blocks any message that fails alignment—even if the sender is a known, legitimate platform like HubSpot.

Let’s say your email list includes addresses at a major bank. Their DMARC policy may require all incoming mail to come only from their approved IP ranges. If HubSpot sends using a shared IP pool that isn’t in that allowlist, the email won’t pass, and the server sends back a 5.7.13 error. The address is technically valid, but it’s not trusted by the receiving domain.

Why Verification Tools Catch What Other Checks Miss

Standard email validation checks syntax, domain existence, and basic MX lookup. But these don’t reveal whether a domain actively blocks known third-party senders, even with valid email formats.

This is where real-time verification tools step in. They simulate actual SMTP delivery attempts—not just to check if an address exists, but to see how the recipient server responds. If repeated attempts fail with a 5.7.13 response, the tool flags it as a high-risk bounce, even if the address is not invalid.

For example, a tool like bulk email list cleaning can identify these cases across thousands of emails, surfacing domains that reject HubSpot traffic specifically, not because the address is wrong, but because their policy is too strict.

The same applies to sender reputation and greylisting. A domain may temporarily delay or reject messages based on IP reputation—even if the sender is legitimate. Tools that test delivery behavior over time can surface these risks before campaigns launch.

According to RFC 7483, DMARC failures are designed to be handled at the recipient’s discretion, meaning even legitimate senders can be blocked if policies aren’t configured to allow them. That’s why verifying the actual delivery behavior—beyond just syntax or domain validity—is crucial.

If your list includes high-security domains, ignoring SMTP-level rejection patterns means you’ll keep paying for failed sends. Prevention isn’t about guessing; it’s about testing the actual delivery path.

How Email List Validation Integrates with HubSpot to Block 5.7.13 Errors

You can prevent 5.7.13 DMARC violations in HubSpot by verifying email addresses in real time during syncs using the Email List Validation API. This stops invalid or risky domains from entering your CRM, reducing bounces and protecting sender reputation. The tool flags domains with a history of DMARC rejections and lets you clean lists before sending, all within HubSpot’s workflow environment.

Real-time verification during HubSpot syncs

• Use the Email List Validation API to validate every email address as it syncs into HubSpot from forms, imports, or third-party tools.
• Automatically reject deliveries to invalid or high-risk domains before they trigger a 5.7.13 bounce in SMTP logs.
• Integrate with HubSpot’s native API to verify leads during capture or on scheduled batch imports—no manual steps required.

Automate suppression of risky domains

• Set up rules in HubSpot to automatically flag or block contacts from domains that have previously returned 5.7.13 or other DMARC-related errors.
• Let Email List Validation track domain behaviors via its global database of known rejecting domains and deliverability patterns.
• Use the tool’s in-app AI assistant to analyze flagged domains—get a summary of risk type (e.g., catch-all, greylist, role-based) and recommended actions directly in HubSpot.
• Review recommendations like “contact via alternate channel” or “validate manually” and act without leaving the platform.
• Save time and reduce deliverability risks by cleaning entire lists before sending via the bulk verification feature.

According to RFC 7505, 5.7.13 is a permanent SMTP rejection indicating a DMARC policy failure. These errors signal that your domain’s authentication failed at the recipient side, which harms long-term sender reputation.

Let’s be clear: DMARC violations aren’t just about bounces. They contribute to IP reputation decay and increase the odds of being flagged by Spamhaus or other blocklists. Using Email List Validation to catch risks at the source—before they hit HubSpot or your email service provider—avoids unnecessary strain on your sending infrastructure.

For detailed testing, integrate with inbox placement tests to verify delivery success in real consumer inboxes across major providers.

The Cost of Ignoring 5.7.13 in Your HubSpot Campaigns

Each 5.7.13 bounce from a Microsoft recipient isn’t just a failed send — it’s a reputational hit. Over time, repeated bounces degrade your sender reputation, increasing the risk of being blocked by Microsoft’s filtering systems, even if your content is valid. A single failure to a high-traffic domain like outlook.com can lower inbox placement across all domains, not just that one.

How 5.7.13 Bounces Hurt Your Sender Reputation

When HubSpot sends to an email address that fails DMARC validation — returning a 5.7.13 error — it signals to Microsoft’s filtering engine that your sending infrastructure isn’t properly aligned with the domain’s authentication rules. Every instance adds to your reputation score penalty. While a single bounce may not trigger immediate blocklisting, repeated offenses are a red flag to Microsoft’s systems.

This isn’t hypothetical. Microsoft’s own documentation on SMTP error codes confirms that 5.7.13 is tied to DMARC misalignment, which is a core factor in their spam and deliverability decisions. The longer you ignore these bounces, the slower your delivery velocity becomes across all domains, not just Microsoft’s.

Why High-Volume Domains Amplify the Damage

If you’re sending to a large number of addresses at outlook.com, hotmail.com, or live.com, even one address with a misconfigured or invalid DMARC policy can trigger a 5.7.13 bounce. Since Microsoft treats such bounces as authentication failures, not just invalid addresses, the impact scales.

And because sender reputation is shared across your IP and domain, a single bad batch to a Microsoft domain can reduce deliverability for all your emails — including those to Gmail, Yahoo, and other inboxes. The damage isn’t contained.

Let’s be clear: you can’t rely on HubSpot’s built-in list hygiene alone. You need to verify email addresses before sending, especially those linked to domains with strict DMARC policies. Real-time validation catches invalid, catch-all, or role-based emails before they trigger bounces.

With Email List Validation, you can proactively clean your HubSpot lists to remove bad addresses — including those that would trigger a 5.7.13 error — before they ever hit the wire. Our bulk verification process scans your list for invalid, disposable, and catch-all addresses in seconds. Try it with 100 free verifications at bulk email list cleaning.

Accuracy and Coverage: What You Should Expect from a Reputable Tool

Real-world testing shows Email List Validation delivers 98.9% accuracy across major domains and providers, catching invalid addresses, catch-alls, and delivery blockers like 5.7.13 before they hit your inbox. It doesn't just scan syntax—it speaks to the receiving server directly, validating the entire delivery path, which is what stops DMARC errors at scale.

SMTP-Level Validation Catches 5.7.13 Before It Happens

Unlike simple syntax checks, Email List Validation performs actual SMTP handshakes. This means it can detect rejection codes—like 5.7.13, which signals DMARC policy failure—before you ever send. If a domain blocks emails from your sender IP due to DMARC alignment issues, the tool identifies that during verification.

Let’s say you’re sending from [email protected] to a user at example.com. If example.com’s DMARC policy rejects messages from unrecognized senders, the server will respond with 5.7.13 during the SMTP connect. Email List Validation catches that response in real time and flags the address as risky or invalid.

Domain-Level Pattern Recognition Stops Recurring Issues

It’s not just about individual emails. If a domain consistently returns 5.7.13 or other delivery errors, the system flags that domain for further review. This prevents you from repeatedly targeting problematic domains, which harms your sender reputation over time.

Over time, these patterns help you refine your list. You’re not just cleaning errors—you’re learning which domains are aligned with your sending setup and which aren’t. That’s how you maintain sender reputation without guessing.

If you’re using HubSpot, this is especially valuable. HubSpot’s marketing automation relies on clean, deliverable data. Sending to addresses that get rejected due to DMARC can trigger alerts in HubSpot’s delivery reports and even harm your domain reputation with email providers like Gmail and Microsoft. Using a tool that verifies at the SMTP layer is how you prevent those issues before they affect your campaigns.

For continuous validation at scale or in real-time, you can integrate Email List Validation with HubSpot, Mailchimp, or Klaviyo through our integrations. You can also test bulk lists for inbox placement and deliverability using our inbox placement reports, which simulate real-world delivery across inboxes like Gmail, Outlook, and Apple. For smaller checks, our API allows instant validation during signup or onboarding.

Standard email validation tools don’t always verify at the SMTP level. Many rely on domain reputation databases or simple pattern matching—but those won’t catch 5.7.13. The real test is seeing how the receiving server responds, and that’s exactly what Email List Validation does. For a full breakdown of how deliverability works, see the DMARC RFC or Spamhaus’s guide to DMARC.

Prevent 5.7.13 Errors Before They Happen: A Smart Deliverability Habit

Every new email list is a potential source of 5.7.13 DMARC failures. Never assume inbox placement will be clean. Verify before you send.

Integrate real-time validation into your HubSpot workflow

Automate the purge of invalid, risky, or catch-all addresses before they trigger delivery failures. Real-time checks prevent bounces and protect sender reputation at scale.

Monitor at the SMTP level, not just the delivery level

Success rates alone hide risk. Track hard bounces, greylist responses, and DNS-level feedback to clean lists based on actual sender reputation signals — not just soft deliverability metrics.

Keep reading

• Email authentication and encryption: SPF, DKIM, DMARC, TLS (complete guide)
• Email Validation API That Simulates TLS Handshake for AWS SES Pre-Send Checks 2025
• SPF Alignment Failure 5.7.14 Amazon SES Trace Analysis 2026 Guide
• Pipedrive CRM Email Sync Failure Due to Outdated TLS: 2026 Fixes
• Ensure High Email Deliverability Through Salesforce SMTP Verification 2025

Ready to put this into practice? Email List Validation verifies emails with 98.9% accuracy — start with 100 free verifications.

Frequently asked questions

Can 5.7.13 errors happen even with a valid email address?

Yes. 5.7.13 is a server-level rejection due to DMARC policy violation, not address validity. An address may be syntactically correct but blocked by the receiving domain’s policies.

Does email verification fix DMARC misalignment?

No. Verification does not fix alignment between the sending domain and the email’s 'From' field. But it prevents sending to domains likely to reject mail based on DMARC.

How often should I verify my HubSpot list?

At least once before every major sending campaign and monthly for ongoing list hygiene.

What does the 'risky' verdict mean in Email List Validation?

It indicates the domain shows signs of instability—repeated transient errors like 5.7.13, slow responses, or intermittent delivery failure.

Can disposable email domains cause 5.7.13 errors?

No. Disposable domains typically return early SMTP rejections, not 5.7.13. However, they still harm deliverability and should be removed.

How does Email List Validation detect 5.7.13?

It performs real SMTP checks during the verification process and logs specific error codes returned by the receiving server.

What’s the difference between 5.7.13 and 5.1.15?

5.7.13 is a DMARC-related rejection; 5.1.15 is a general delivery failure. 5.7.13 specifically indicates policy misalignment or lack of authentication.

Is HubSpot responsible for DMARC failures?

No. HubSpot acts as a relay. The failure occurs when the recipient server enforces its own DMARC policy and rejects mail due to misalignment.

Can I verify emails directly in HubSpot?

Not natively. But by using Email List Validation’s API, you can verify and clean lists before syncing them into HubSpot.

How do I know if a domain is DMARC-protected?

Check the DNS record using tools like MxToolbox. Domains with a DMARC record usually include policy enforcement.