"Temporarily rate limited" ? from Google in mail relay.
For a short period, I've setup Postfix mail relay on my vhost to forward my @domain.com email to my gmail account. Mind you, I've had this email address and domain for over 14 years -- it gets a lot of spam (which is a big reason why I use Gmail for its awesome filters).
While watching the logs, I got this message (pretty quickly) from Google's SMTP server:
Our system has detected an unusual rate of 421-4.7.0 unsolicited mail originating from your IP address. To protect our 421-4.7.0 users from spam, mail sent from your IP address has been temporarily 421-4.7.0 rate limited. Please visit 421-4.7.0 http://www.google.com/mail/help/bulk_mail.html to review our Bulk 421 4.7.0 Email Senders Guidelines. f14si1032016icj.42 - gsmtp (in reply to end of DATA command))
(I've since moved the MX record back to the original shared host to insure mail works)
The thing is, I'm not bulk emailing. I'm simply trying to setup a mail relay for my custom domain. Google saw "an unusual rate (was actually only about 5) of unsolicited mail" being forwarded over simply because my address is spammed ... a lot.
Is there anything I can do to alleviate this? The need of a mail relay host is actually a huge issue. This is preventing me from fully moving off my current shared hosts (A2Hosting & Dreamhost).