Mail Analyzing Interface for email bounce: A Perl module to parse RFC5322 bounce mails and generating structured data as JSON from parsed results. Formerly known as bounceHammer 4: an error mail analyzer.
Sisimai detects the following error message returned from Google as NotCompliantRFC
host aspmx.l.google.com[142.251.170.26] said: This message is not RFC 5322 compliant.
There are multiple Subject headers. To reduce the amount of spam sent to Gmail,
this message has been blocked.
Please visit https://support.google.com/mail/?p=RfcMessageNonCompliant and review RFC 5322
specifications for more information.
c2-aguiqyuiyuqir5678167856aeu8.22 - gsmtp (in reply to end of DATA command)
NotCompliantRFC