Summary
The '552 5.2.0 sender rejected AUP#POL' email error signals a permanent delivery failure due to the sending server violating the recipient's Acceptable Use Policy (AUP). This stems from sender-side issues, like poor reputation or policy breaches. Cloudmark is often involved. Resolution involves determining the email provider, reviewing their AUP, authenticating emails (SPF, DKIM, DMARC), checking blacklists, and contacting the provider. New sending domains are also often associated with spammers which can trigger the errors, as well as suspicious keywords being used in the body of the emails.
Key findings
- Permanent Error: 5xx SMTP errors (like 552) signify permanent failures; emails won't be delivered.
- Sender Problem: It’s generally a sender-side issue, caused by poor reputation or policy violations.
- AUP Violation: AUP#POL means the sender violated the recipient's Acceptable Use Policy.
- Need Specifics: While the error is broad, precise action requires checking with the email provider causing the error.
- Cloudmark often in use: Email Servers may be using Cloudmark.
Key considerations
- Identify the Provider: Determine which email provider caused the rejection to know their policy.
- Review the AUP: Read the recipient's AUP to find what triggered the rejection.
- Authentication is Key: Ensure SPF, DKIM, and DMARC are correctly set up.
- Check Blacklists: Verify your IP isn't on any email blacklists.
- Contact Support: Reach out to the email provider's support for guidance.
- Content review: Review the email content to ensure you do not have spam trigger words.
- Domain Age: Ensure the sending domain is not new.
What email marketers say
7 marketer opinions
The '552 5.2.0 sender rejected AUP#POL' email error indicates a permanent delivery failure due to a violation of the recipient's Acceptable Use Policy (AUP). The 'POL' portion refers to a specific policy. Resolution involves identifying the recipient's email provider, reviewing their AUP, ensuring proper email authentication (SPF, DKIM, DMARC), maintaining a good sender reputation, avoiding spam trigger words in content, checking if the sending domain is newly registered and associated with spammers, and contacting the recipient's provider for clarification and delisting if necessary.
Key opinions
- AUP Violation: The error signifies a violation of the recipient's email provider's Acceptable Use Policy (AUP).
- Permanent Failure: 5xx errors, like 552, are permanent, indicating the email will not be delivered and should not be retried.
- Sender-Side Issue: The error generally points to a problem with the sender's email practices or reputation, triggering filters on the receiving server.
- New Domain Issue: Newly registered domains used for sending can trigger this error due to their association with spam activities.
Key considerations
- Identify Recipient Provider: Determine the specific email provider causing the bounce to understand their AUP requirements.
- Review AUP: Carefully review the recipient's email provider's Acceptable Use Policy to identify the specific violation.
- Check Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) is in place to verify the sender's identity.
- Monitor Reputation: Monitor sender reputation and IP address on blacklists to identify potential issues affecting deliverability.
- Content Review: Review email content for spam trigger words and phrases that may trigger filters.
- Contact Provider: Contact the recipient's email provider for clarification on the AUP#POL code and request delisting if necessary.
Marketer view
Marketer from Email Geeks reveals the issue was related to the age of the domain seen in the PTR record for the sending IPs. The domain was new and registered via a provider favored by spammers.
5 Jan 2025 - Email Geeks
Marketer view
Email marketer from StackOverflow shares that resolving 552 errors typically involves ensuring that your sending domain has proper authentication (SPF, DKIM, DMARC), maintaining a good sender reputation, and adhering to email sending best practices to avoid being flagged as spam. Also, they suggest contacting the recipient server administrator for specifics.
18 Dec 2022 - Stack Overflow
What the experts say
5 expert opinions
The '552 5.2.0 sender rejected AUP#POL' error signifies a sender-specific problem related to policy violations. The 'sender rejected' message indicates the sending platform's reputation is the issue, not the recipient. The rejection can originate from servers like Cloudmark. Resolving it requires identifying the rejecting server (checking the banner helps), understanding the specific recipient ISP's Acceptable Use Policy (AUP), checking sender reputation against blacklists, and ensuring proper email authentication (SPF, DKIM, DMARC). Contacting the ISP to understand the specific violation is crucial.
Key opinions
- Sender Specific: The error is specific to the sending platform's reputation, not the recipient's address.
- Cloudmark Involvement: Cloudmark (cloudfilter.net) is often involved in these rejections.
- AUP Violation: The AUP component indicates a violation of the recipient ISP's Acceptable Use Policy.
- Policy Check Failure: The 552 error points to the sender failing a policy check.
Key considerations
- Check Server Banner: Check the banner of the rejecting server to identify the responsible entity.
- Review ISP's AUP: Carefully review the specific ISP's Acceptable Use Policy to pinpoint the violation.
- Check Reputation: Check the sender's IP and domain reputation against common blacklists.
- Ensure Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) is configured correctly.
- Contact ISP: Contact the recipient's ISP to understand the specific policy being violated and for resolution guidance.
Expert view
Expert from Word to the Wise responds by explaining that while the exact meaning of 'AUP#POL' can vary, the 552 error points to the sender failing a policy check. They would start by checking the sender's IP and domain reputation against common blacklists, ensuring proper authentication (SPF, DKIM, DMARC) is configured, and then contacting the recipient's ISP to understand the specific policy being violated.
22 Nov 2021 - Word to the Wise
Expert view
Expert from Email Geeks shares that the servers causing the rejection are run by Cloudmark, operating under the banner of cloudfilter.net, even if the IPs are in AWS.
10 Oct 2021 - Email Geeks
What the documentation says
4 technical articles
The '552 5.2.0 sender rejected AUP#POL' error indicates a permanent email delivery failure due to a policy violation. The error suggests a problem with the sender's practices or a violation of the recipient's Acceptable Use Policy (AUP), as seen particularly with Cox. While the error indicates a general policy refusal, further investigation is needed with the recipient's email administrator to understand the specifics. General troubleshooting steps include ensuring correct email authentication (SPF, DKIM, DMARC) and verifying the sender's IP isn't blacklisted.
Key findings
- Permanent Failure: 5xx SMTP errors signify a permanent failure, and the email won't be delivered.
- Policy Violation: The AUP#POL code indicates a violation of the recipient's Acceptable Use Policy.
- Sender-Side Issue: The error points to problems with the sender's email or sending practices.
- Further Investigation Needed: Specific resolution requires further investigation with the recipient's mail server administrator.
Key considerations
- Review AUP: Review the recipient's Acceptable Use Policy to identify the specific violation.
- Ensure Authentication: Verify SPF, DKIM, and DMARC records are correctly configured for email authentication.
- Check Blacklists: Ensure the sender's IP address is not blacklisted.
- Contact Recipient Support: Contact the recipient's support for specific guidance on the AUP#POL code.
Technical article
Documentation from Microsoft Learn explains that SMTP 5xx errors are permanent failure codes. While it does not explicitly address 'AUP#POL', the documentation points to the general class of 5.2.0 errors meaning that the mail server encountered a permanent error, but it doesn't know enough to be more specific about the error. Further investigation of the specific error from the recipient's mail server administrator is needed.
5 Dec 2022 - Microsoft Learn
Technical article
Documentation from DigitalOcean.com provides general guidance on diagnosing email bounce issues, advising to check SPF, DKIM, and DMARC records to ensure proper email authentication. Additionally, it suggests verifying the sender's IP address isn't blacklisted and to ensure compliance with the recipient's email provider's policies.
20 Jul 2021 - DigitalOcean.com
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