Domain being rate limited sending to addresses?

Since approximately 5-30-2018 8:48 AM EST messages to "" addresses appear to be rate limited. Retrying the messages later only results in the same delaying. We are a high volume sender as this is what our users request. Every subscriber is double opt-in AND mobile verified. Here is what we are seeing with specific information removed for privacy:


This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its

recipients. This is a permanent error. The following address(es) failed:

host [52.201.XX.XX]

SMTP error from remote mail server after MAIL FROM:<> SIZE=1578:

452 4.1.0 <> requested action aborted:

try again later: retry timeout exceeded


Reporting-MTA: dns;

Action: failed

Final-Recipient: rfc822;

Status: 5.0.0

Remote-MTA: dns;

Diagnostic-Code: smtp; 452 4.1.0 <> requested action aborted: try again later: retry timeout exceeded


Our MTA is reporting: R=dkim_lookuphost T=dkim_remote_smtp defer (-53): retry time not reached for any host for '

I sent an initial request to Cloudmark ( thinking it was an issue with their server blocking us, however, their cursory report shows it is NOT them... "The SMTP rejection that you have received is not the result of current data provided by Cloudmark Sender Intelligence."

Could someone help me resolve this issue or provide us with a better contact? Placing this discussion into a private setting will enable us to reveal more specific details.



Labels (1)
2 Replies
Champion - Level 3

Do you get the same results using the domain

...Just another VZW customer...trying to offer some assistance...

This is not something we have tested at this time.