# 6.1.0.0gbb8c210e: DKIM fails on auto-generated

**URL:** <https://community.ciphermail.com/t/6-1-0-0gbb8c210e-dkim-fails-on-auto-generated/1015>\
**Category:** Gateway\
**Created:** [September 29, 2025, 11:08am UTC](https://community.ciphermail.com/t/6-1-0-0gbb8c210e-dkim-fails-on-auto-generated/1015 "2025-09-29T11:08:26Z")\
**Posts on this page:** 1\
**Page:** 2

<div class="post-metadata">

**Author:** ![martijn](https://dub1.discourse-cdn.com/flex017/user_avatar/community.ciphermail.com/martijn/32/127_2.png) [@martijn](https://community.ciphermail.com/u/martijn)\
**Post date:** [September 30, 2025, 4:30pm UTC](https://community.ciphermail.com/t/6-1-0-0gbb8c210e-dkim-fails-on-auto-generated/1015/21 "2025-09-30T16:30:51Z")

</div>

Good to hear it is fixed.

What happened was that locally generated email, for example an invitation for  
the portal or a “forgot password” email, did not have the date header set. The  
back-end than DKIM signed the email with the missing date. After handling , the  
back-end sends the email to Postfix for delivery. Postfix by default however  
adds certain header fields to the email if they are missing (data, to, from,  
message-id). Because the message was DKIM signed without a date header, adding  
the date header to the email caused the DKIM signature to be invalid.

The system was modified to ensure that all locally generated emails include a  
date header. An alternative approach would have been to configure Postfix by  
setting the local\_header\_rewrite\_clients parameter to an empty value, which  
prevents the mail server from automatically adding missing headers.

[Previous page](https://community.ciphermail.com/t/6-1-0-0gbb8c210e-dkim-fails-on-auto-generated/1015.md?page=1)