while investigating a DKIM problem, this messages was found:
2021-10-04 14:38:43 1mXNEx-0057RV-3Q H=sender.de [sender-ip]
X=TLS1.3:TLS_AES_256_GCM_SHA384:256 CV=no rejected DKIM 1084 LAST: Mail
from sender-domain.de with invalid
a) invalid what???
I think a complete message would be nice ;)
b) while your on it:
it was a missing DNS TXT-record for the selector subdomain, so the
message should reflect it. If the sig is false/broken, the message
created should reflect that, so debugging problems easier would be nice.
A general "it failed" messages is not helpfull.
If diversification of causes is already implemented, forget b) ;)
