Mail server's hoster blocked by uceprotectip3 - unable to send mail to Email Forwarded domains

My mail server at is not able to send email to domains with Email Forwarding enabled.
I’m getting the following error:

<[email protected]>: host[] said: 554 found on one or more DNSBLs (uceprotectip3). Refer to
    for more information.  (in reply to RCPT TO command)

Upon investigating the blacklist, it seems that UCEProtect has blocked the hoster of the mail server (AS51167 - Contabo). To clarify, every other anti-abuse service and UCEProtect itself isn’t flagging the mail server’s IP.

I think such blacklist is too broad and will cause a lot of false-positives. Personally, I think you should exclude uceprotectip3 - ASN block, from the filters.

That ASN looks pretty hot right now, spam-wise:

It’s also an ASN I’ve personally blocked due to constant malicious probing of many of my websites.

As a personal note, running your own mail server is going to cause you a lot of heartache because of IP address reputation. Especially when it’s on a VPS service with lots of abusive users.


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