Gmail rejecting emails sent via SES

Question

I use SES, currently without dedicated IPs. For the last 3 days I've seen the following type of error:

{"emailAddress":"@gmail.com","action":"failed","status":"4.4.7","diagnosticCode":"smtp; 554 4.4.7 Message expired: unable to deliver in 840 minutes.<421-4.7.28 [54.240.8.50      15] Our system has detected an unusual rate of421-4.7.28 unsolicited mail originating from your IP address. To protect our421-4.7.28 users from spam, mail sent from your IP address has been temporarily421-4.7.28 rate limited. Please visit421-4.7.28  https://support.google.com/mail/?p=UnsolicitedRateLimitError to421 4.7.28 review our Bulk Email Senders Guidelines. d19-20020a0cdb13000000b006418e876d0bsi8784215qvk.10 - gsmtp>"}

This is only affecting Gmail addresses, not other email services. I've moved to standard managed IPs but those IPs need time to warm up. Is there anything I can do in the meantime to reduce these bounces?

Answer

Hello,

Two things come to mind
1) Have you setup already the domain authentication (spf, dkim, dmarc)?
2) Do you see any issues with the domain reputation on SES dashboard, things such as a significant bounce rate from previous sending activities? This usually takes some time and actions to remediate and clear out

You can also check the IP in question against known potentially problematic IP's, see if anything comes up (example barracuda block list)

Gmail rejecting emails sent via SES

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