Mail server throttling issue
Since we moved to Comcast Business internet on 6/24 we have been seeing issues with messages to customers being throttled on a mail server. These messages must go out in a timley manner because they are letting customers know that items are ready to be picked up at thier local library.
Can you white list us or something like that to stop the throttling?
Log message below. Email user name and IP redacted for privacy reasons.
50 *** sendmail: x6K9QJ70015596: to=<firstname.lastname@example.org>, delay=22:06:30, xdelay=00:00:01, mailer=esmtp, pri=2191366, relay=mx1.comcast.net. [IP Address Redacted], dsn=4.0.0, stat=Deferred: 421 4.1.0 22.214.171.124 Throttled - try again later. Please see http://postmaster.comcast.net/smtp-error-codes.php#RL000003
I also saw a similar post in the Xfinity forum. Not sure if that helps, link here: https://forums.xfinity.com/t5/Email-Web-Browsing/Mail-Server-Throttling-and-Connection-Problems/td-p/3245002