Email fails domain authentication
Error message seen in conjunction with an email going in to junk email.
This email has failed its domain's authentication requirements. It may be spoofed or improperly forwarded!
How you would notice :
You've drafted your email and send a test to your email, but it (prob) goes into 'junk' and also have this error message shown above.
Something wrong with the reply-to email (actual reason to be established!)
Temporary fix Try sending another test with firstname.lastname@example.org, if this works - either use this email as your reply to or another email of your choice that doesn't give the error.
Permanent Fix coming soon!