I added a new domain to my SmarterMail email server a few months. It seems that this domain intermittently emails to GMail accounts are never delivered. As an example I impersonated one of the email accounts that has been sending these emails that get lost going to GMail accounts. I was on the telephone with the GMail recipient when I sent them a test message from SmarterMail to their GMail account. They received that message no problem. Please note they do have a contact setup in GMail with the SmarterMail email address sending these emails to prevent them from going to Junk/Spam. I sent them a second message with a read receipt request with no attachments and added a 2nd YMail recipient who is also having the same problem. Neither one of them received the 2nd email. I didn't get a delivery failure. The GMail recipient checked the Junk/Spam folder, there deleted folder and every other folder they have but did not receive the 2nd email. The 1st test email was delivered to their Inbox successfully. It seems only to happening with GMail and YMail. We have DKIM setup properly on the domain. I just can't understand how 1 email can be delivered successfully and a few minutes later the 2nd email is lost in cyber space never to be delivered and never generate a delivery failure. Obviously the email address is correct if it got delivered successfully the 1st time. I would also like to note I have another domain on the same SmarterMail server with approximately 250 email accounts and no one on that domain has complained about this problem.
Has anyone ever experienced this problem? Is there a log file I can check to see if GMail accepted the email? I would appreciate any suggestions on how to solve this. Thanks in advance for your help.