DKIM alignment value is invalid
ATTENTIONWhat it means
adkim=the offending value is not valid, so receivers use relaxed alignment. If you intended strict, you are not getting it.
How to fix it
Use adkim=r for relaxed or adkim=s for strict.
Check your own domain
This page describes the condition. To find out whether your domain has it, run the DMARC test or the full checkup, which examines every record at once.
Understand it properly
This page covers one condition. For the whole picture, The DMARC guide, from a first record to enforcement, or start at the Health Library.
Where this comes from
We judge this against RFC 9989 section 4.7. Every finding on this site cites the specification behind it so you can check the work rather than take our word for it.
Other DMARC conditions
DMARC_ADKIM_INVALID
Every fix on this site is yours to implement. If you would rather someone did it, I take this work directly.