I have email accounts at the hosting service that hosts my CiviMail 4.6.2 in WordPress 4.1.7. The accounts forward mail to other addresses. I.e. CiviCRM is on www.mydomain.com and the addresses are @mydomain.com, but the mail is forwarded elsewhere.
Non-CiviMail email from CiviCRM to these @mydomain.com addresses is received but CiviMail is reported as "success" but is never received, not seen as spam. CiviMail to other addresses (@elsewhere.com) is received. (In a CiviMail mailing that includes both @mydomain.com and @elsewhere.com the @elsewhere.com posts arrive and @mydomain.com posts don't.)
CiviMail to @mydomain.com used to work, apparently stopped several months ago.
What configuration should I be looking at in order to get this going again?
(Most, but not all, of the @mydomain.com addresses forward to Google Apps mail servers. However the non-receipt affects all @mydomain.com addresses, not just the ones handed on to ASPMX.L.GOOGLE.COM .)