Mailing lists often rewrite headers and bodies, breaking DKIM. Learn why and what to do about it.
Mailing list servers commonly modify messages by adding footers, changing subjects, or rewriting headers. These changes can break DKIM signatures because DKIM signs specific message parts.
To reduce issues, send with DKIM that can survive minimal changes, encourage ARC on list servers, and use DMARC policies with careful rollout. For communities, this is a known challenge.