Our system has detected an unusual rate of 421-4.7.0
Mail not being delivered, check the logs
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
Did you set a SPF record and set up DKIM? Email with out them will often run afoul of Gmail:
To ensure that Gmail can identify you:
- Use a consistent IP address to send bulk mail.
- Keep valid reverse DNS records for the IP address(es) from which you send mail, pointing to your domain.
- Use the same address in the 'From:' header on every bulk mail you send.
We also recommend the following: