Some of my email messages (sent from mydomain.com) just fail, message is returned with the following explanation:
Delivery to the following recipient failed permanently: firstname.lastname@example.org Technical details of permanent failure: Message rejected by Google Groups. Please visit http://mail.google.com/support/bin/answer.py?hl=en&answer=188131 to review our Bulk Email Senders Guidelines. ----- Original message -----
I have no idea what Google has got to do with it? How do I avoid this?