Why is my DKIM body hash failing and how do I fix it?

Email marketer from Valimail shares that common causes include: line ending changes, character encoding issues, or modifications by intermediaries like email security services. Also URL rewriting by security services. It is important to check for these issues in the sending process.

Email marketer from Email Geeks shares that line breaking could be the issue as even adding or removing a single space between signing and delivery would cause the hash to fail. They ask if it's happening on every message because If it's only the odd one or too it could take you more time to try and debug than it's actually worth....

Email marketer from Email Geeks shares that if you have an email security service sitting in front of your mailbox provider and it's doing any changes to the body, it'll break the hash (basically scenario Steve mentioned earlier). Changing line breaks or url rewriting will definitely break a body hash, for instance

Email marketer from Stack Overflow explains that some SMTP servers modify email content (e.g., adding tracking pixels or disclaimers) after DKIM signing, leading to a body hash mismatch. It may be necessary to configure exceptions or change SMTP server settings.

Email marketer from SparkPost emphasizes the need to correctly implement DKIM. A good start is to ensure that the DKIM key is valid and that the domain record is configured correctly. Then, ensure the content doesn't change in transport.

Email marketer from EasyDMARC advises reviewing the entire email flow from sender to recipient. Identify any intermediate servers or services that might be altering the email content. Ensure DKIM signing occurs after any content modifications.

Email marketer from DMARCian shares that third-party services such as link trackers, survey tools, or forwarding services can introduce changes to the email body, leading to DKIM failure. Try to disable these services temporarily to identify if they cause it.

Email marketer from MXToolbox suggests using their 'Email Header Analyzer' to examine the email and spot any body-altering changes to the message. It is a valuable tool for quickly diagnosing a DKIM issue.

Email marketer from Mailgun suggests that encoding issues can cause body hash mismatches, especially with special characters or non-ASCII text. Ensure that the email is encoded in UTF-8 and that the DKIM signing process correctly handles the encoding.

Email marketer from Email on Acid explains that it is important to use a DKIM validator or testing tool to verify the signature. These tools show the raw email data and help identify if/where the signing process is breaking.

Email marketer from Reddit user shares common problems like incorrect line breaks, added spaces, or character encoding changes can lead to a DKIM body hash failure. Test emails thoroughly to catch these issues.

Expert from Email Geeks shares that if the DKIM body hash fails, nothing is passing and DKIM is failing.

Expert from Email Geeks explains If the body hash doesn’t verify, DKIM will fail.

Expert from Spam Resource shares that if there are intermediate servers altering the email before it's delivered, then the body hash will fail. You need to identify all mail relays used.

Expert from Email Geeks explains if the hash fails to verify, that indicates that the hash generation is the problem and if the hash doesn’t verify DKIM will never pass.

Expert from Word to the Wise explains that problems come when services modify the content after signing. This can be due to content modification or encoding changes, and should be corrected at the signing stage.

Expert from Email Geeks shares potential causes for DKIM failure: not signing correctly or the message being modified en-route. Since the messages aren't DKIM signed, if you care about DKIM, very serious.

Documentation from Oracle explains that it's important to configure outbound email settings to ensure correct DKIM signing. It's important to verify the selector, the key and make sure that the signing takes place before any modifications to the email can occur.

Documentation from Microsoft explains that Exchange servers are known to alter messages during transport. Therefore, the DKIM signing should occur AFTER any Exchange-related transport rules, in order to be valid.

Documentation from Postmark shares to examine the raw email message (including headers and body) before and after sending to identify any content changes. Compare the DKIM signature in both versions to pinpoint the issue.

Documentation from GitHub (OpenDKIM Wiki) explains using debugging tools like `opendkim-testkey` to check the DKIM signature and identify issues with body hash generation. Correct configuration and key management are crucial.

Documentation from AuthSMTP Support shares that ensure the email body is not altered after DKIM signing. This includes checking for any automatic additions of footers, disclaimers, or tracking pixels by your email service provider or SMTP server.

Documentation from RFC Editor explains that a DKIM body hash failure indicates the body of the message has been altered between signing and verification. This can happen due to content modification or encoding changes.