Summary
DKIM validation failures in cPanel can arise from multiple factors involving DNS configuration, record syntax, key management, and data integrity. TXT records contain multiple strings and DNS record length limitations can cause records to be truncated. Key problems include the public key being unfindable, malformed, not matching the private key, or being of insufficient size. DNS errors during configuration, data corruption by DNS hosts (specifically buddyns.com), and DNS caching issues contribute to validation failures. Additionally, altered message content in transit can invalidate signatures, and syntax errors within the DKIM record itself can also cause failures. Routine testing of DKIM records is therefore crucial.
Key findings
- TXT Record Structure & Length: TXT records contain multiple strings, but DNS record length limitations can truncate DKIM records.
- Public Key Problems: The public key can be unfindable, malformed, mismatched with the private key, or of insufficient size.
- DNS Errors & Corruption: DNS errors during configuration, data corruption by DNS hosts (particularly buddyns.com), and DNS caching issues contribute to failures.
- Message Content Alteration: Altered message content in transit can invalidate DKIM signatures.
- Syntax Errors: Syntax errors within the DKIM record, like extra spaces or incorrect characters, can cause validation failures.
- Incorrect Selector: An incorrect selector in the DKIM record can cause validation failures.
- Multiple DKIM records: Having multiple DKIM records can cause problems
Key considerations
- Record Validation: Regularly test DKIM records using online tools to identify and resolve issues promptly.
- DNS Configuration Review: Carefully review DNS configuration for errors, corruption, or incomplete propagation.
- Key Management: Ensure the public key is valid, matches the private key, and is of sufficient size (2048 bits recommended).
- Content Integrity: Minimize potential alterations to message content during transit.
- Record Syntax: Thoroughly check the DKIM record syntax for any errors or invalid characters.
- Avoid Problematic Services: Refrain from using services like buddyns.com that can corrupt DNS data.
- Selector Verification: Verify the DKIM selector in the DNS matches the one used for key generation.
- Record Consolidation: Ensure only one valid DKIM record is active for the domain.
What email marketers say
8 marketer opinions
DKIM validation failures in cPanel can stem from several issues, including syntax errors within the DKIM record (such as extra spaces or incorrect characters), an incorrect selector that doesn't match the key generation, conflicting multiple DKIM records, DNS record length limitations leading to truncation, and the public key in the DNS not matching the private key used for signing. DNS caching can also prevent immediate recognition of record changes. Regular testing with tools like Mail-Tester and online DKIM checkers is essential to identify and resolve these issues.
Key opinions
- Syntax Errors: Syntax errors, such as extra spaces or incorrect characters in the DKIM record, can lead to validation failures.
- Incorrect Selector: An incorrect selector in the DKIM record can cause validation failures. Ensure it matches the selector used when generating the DKIM key.
- Multiple Records: Having multiple DKIM records with conflicting information can cause validation issues.
- Record Length: DNS record length limitations can cause DKIM records to be truncated, leading to validation failures. Consider TXT record concatenation.
- Key Mismatch: The public key in the DNS must match the private key used to sign emails; otherwise, DKIM will fail.
- DNS Caching: DNS caching issues can delay recognition of DKIM record changes, leading to temporary validation errors.
Key considerations
- Record Review: Carefully review the DKIM record for any typos, extra spaces, or incorrect characters.
- Selector Verification: Verify that the DKIM selector in the DNS record matches the selector used when generating the DKIM key.
- Record Consolidation: Ensure only one valid DKIM record is active for the domain to avoid conflicts.
- Key Synchronization: Ensure the public and private keys align. Regenerate the DKIM Key if not.
- Regular Testing: Regularly test DKIM records with tools like Mail-Tester and online DKIM checkers to identify validation issues.
- DNS Propagation: Consider that the DNS records take time to propogate across the internet and to flush DNS cache if testing quickly.
Marketer view
Email marketer from EmailOnAcid explains that testing DKIM records with tools like Mail-Tester is essential to identify validation issues before sending emails. They advise regularly checking DKIM status to ensure ongoing deliverability.
23 Sep 2021 - EmailOnAcid
Marketer view
Email marketer from StackOverflow explains that an incorrect selector in the DKIM record can cause validation failures. The selector must match the selector used when generating the DKIM key.
18 Oct 2023 - StackOverflow
What the experts say
4 expert opinions
DKIM validation failures in cPanel can arise from several technical issues. TXT records, which hold DKIM information, can be split into multiple strings. Problems with the DKIM public key can cause failure, which includes the public key not being findable, malformed, or not matching the private key. Also, errors introduced during DNS configuration or data corruption from DNS hosting services are potential reasons. Avoid using buddyns.com as they corrupt data.
Key opinions
- TXT Record Structure: TXT records can contain multiple strings no more than 255 characters, appended by DKIM validators.
- Public Key Issues: Problems with the DKIM public key, like being unfindable, malformed, or mismatched, can cause failures.
- DNS Configuration Errors: Errors during DNS configuration, including quotes or data corruption from DNS hosts, can lead to DKIM failures.
- Data Corruption: Certain services, like buddyns.com, can corrupt DKIM data.
Key considerations
- Verify Public Key: Ensure the DKIM public key is correctly configured, findable, and matches the corresponding private key.
- Avoid Buddyns.com: Refrain from using buddyns.com to prevent data corruption of DKIM records.
- Check DNS Configuration: Carefully review DNS configuration for any errors, such as unwanted characters or corruption by the DNS host.
- Check DNS Host: If DNS host corrupts data you must switch hosts.
Expert view
Expert from Email Geeks concludes that buddyns.com can corrupt DKIM data.
11 Jul 2024 - Email Geeks
Expert view
Expert from Word to the Wise explains that DKIM record failures can be caused by errors introduced during DNS configuration. This includes problems like quotes in the record or DNS hosting services corrupting the data.
13 Feb 2024 - Word to the Wise
What the documentation says
4 technical articles
DKIM validation failures in cPanel can be caused by several technical documentation issues. These include incomplete DNS propagation after adding or modifying DKIM records, alteration of message content during transit, insufficient key size (less than 1024 bits is not recommended), and syntax errors in the public key record.
Key findings
- DNS Propagation: Incorrect DNS propagation can cause DKIM validation failures.
- Content Alteration: DKIM signatures can fail validation if the message content is altered in transit.
- Insufficient Key Size: Using an insufficient key size (less than 1024 bits) can cause DKIM validation to fail; 2048-bit keys are recommended.
- Syntax Errors: The public key record must adhere to specific syntax; invalid characters can cause failures.
Key considerations
- Check DNS Propagation: Ensure DNS records have fully propagated after adding or modifying them.
- Maintain Message Integrity: Minimize the chance of content alterations in transit.
- Use Adequate Key Size: Use a 2048-bit key for stronger security and better compatibility.
- Verify Syntax: Carefully verify the syntax of the public key record for any errors or invalid characters.
Technical article
Documentation from RFC Editor (RFC 6376) explains that DKIM signatures can fail validation if the message content is altered in transit. This includes changes to headers or body content.
7 Jul 2022 - RFC Editor
Technical article
Documentation from cPanel Official Documentation explains that incorrect DNS propagation can cause DKIM validation failures. Ensure the DNS records have fully propagated after adding or modifying them.
2 Feb 2022 - cPanel Official Documentation
Can DKIM be set up on a subdomain, and which domain should be used for signing?
Can email signatures, especially via Exclaimer, cause SPF or DKIM failures and impact email delivery?
How do I fix DKIM alignment errors and configure DKIM signing for a custom domain in Microsoft 365 and is include:spf.mtasv.net required for mailchimp?
How do I fix DKIM failing body hash verification?
How do I set up DKIM with A2 Hosting and troubleshoot validation issues?
How do I troubleshoot DMARC failures and potential DKIM replay attacks affecting email deliverability?
