Compare a passing and failing sample#
Use messages from the same sending system. Record the sending time, selector, signing domain and route. Confirm whether the failure is consistent or isolated to one intermediary. Avoid assuming every Outlook delivery problem is a DKIM problem.
Check transformations and signatures#
Review duplicated headers, forwarding, footers and any service that rewrites messages. If more than one DKIM signature appears, examine the results separately. MailMaid’s analyzer displays reported outcomes; it does not recalculate cryptographic signatures.
Escalate with a useful packet#
Give your provider the original received source, timestamps and relevant message IDs through its secure support process. Include a minimal reproduction. Remove unrelated private message content when it is not necessary for investigation.
Primary references
Consult the current specification or provider guidance when applying these checks.
DKIM specification