Cloudflare blocking emails

[DDehamel]

Once again, Cloudflare is blocking emails from my company to my Shaw Email. This started two days ago and I have missed many important messages from my company and all i get is this

his 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:

  deandehamel@shaw.ca
    host shw-central.mx.a.cloudfilter.net [15.222.199.59]
    SMTP error from remote mail server after MAIL

server temporarily unavailable AUP#MXRT

[DDehamel]

From Cloudmark:

Hi there,

The delivery error, reject or defer message you are seeing is related to a policy decision enforced on behalf of the recipient organisation.

As this policy is designed to protect their end users, we cannot adjust this without their authority. You'll need to contact the recipient organisation and they can escalate to us if necessary.

cheers,

Dug Smith
Cloudmark Customer Support

[mdk]

@DDehamel --  do you mean "CloudFilter" or "CloudFlare" ? Is your server using CloudFlare?

$ nslookup shw-central.mx.a.cloudfilter.net
Name: shw-central.mx.a.cloudfilter.net
Addresses: 3.96.81.40 / 15.222.199.59

$ nslookup 15.222.199.59
Name: ec2-15-222-199-59.ca-central-1.compute.amazonaws.com
Address: 15.222.199.59

For me, both DNS queries work fine. It shows that CloudFilter is using high-volume servers provided by Amazon AWS.

> server temporarily unavailable AUP#MXRT

AUP ==> Appropriate Usage Policy

MX ===> Mail-Exchanger

RT ====>  ? some sort of "routing" issue ?

Is it possible that the DNS-servers for your company have missing/incorrect values, such that when CloudFilter queries your DNS-server, then missing/incorrect values are returned ?

CloudFilter is doing those DNS-queries, to try to detect/block "rogue" and/or "spammer" SMTP-servers.