What goes wrong.
NO SPF OR DKIM
The foundation missing.
TWO SPF RECORDS
Invalidates both.
FORGETTING A SENDING SERVICE
Its mail fails while your ordinary mail is fine.
SENDING AS THE VISITOR'S ADDRESS
The most common cause of form emails failing.
USING A FREE ADDRESS AS SENDER
For business mail, damaging.
SENDING TO PEOPLE WHO DID NOT ASK
Complaints, then blacklisting.
DIFFICULT UNSUBSCRIBE
Produces spam complaints instead.
SENDING TO AN OLD LIST
Bounces and complaints together.
NOT REMOVING BOUNCES
Continued sending to dead addresses.
NOT TESTING
Discovering the problem when a customer mentions it.
RECORDS LOST IN A MIGRATION
Authentication does not travel automatically.
ASSUMING CONTENT IS THE PROBLEM
It is usually authentication or reputation.
