All messages to gmail.com are delayed in the queue(400 4.4.7) and ultimately dropped. sometimes the mail will get delivered a day or two later but most of the time there is an NDR sent to the sender. The mail server can resolve the mx records for gmail.com with issue. If I try to send a test message using telnet I receive the following error:
ehlo conte.com
250-mx.google.com at your service
250-SIZE 35882577
250-8BITMIME
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-CHUNKING
250 SMTPUTF8
mail from:<mail address>
250 2.1.0 OK xb4si5599822igb.59 - gsmtp
rcpt to:<mail address>
250 2.1.5 OK xb4si5599822igb.59 - gsmtp
data
354 Go ahead xb4si5599822igb.59 - gsmtp
this is a test messge 1036
.
550-5.7.1 Our system has detected that this message is not
550-5.7.1 RFC 5322 compliant. To reduce the amount of spam sent to Gmail, this
550-5.7.1 message has been blocked. Please review
550 5.7.1 RFC 5322 specifications for more information. xb4si5599822igb.59 - gsmtp