Blacklisting — Solution Please

I’ve just tried to send an email and have been told via an alert that my IP address has been blacklisted. This is the second time this has happened this year. I work for a not-for-profit and the last time this happened the person who provides my IT support recommended that I get an anti-virus programme and run it 24/7. I tried a few out but they interfered with some of my Mac’s operations. Any suggestions for a solution or a good anti-virus programme?


Email blacklisting generally affects and targets the SMTP server, the server that is sending out your email. This may happen if the server does not require a login and acts as an “open relay”. The reason being that these servers are easily found and taken advantage of by spammers. This will get your server on a blacklist quickly.

A local installation of Antivirus software will not fix this - if that is what’s happening. I have never heard about individual client IPs getting onto email blacklists. (Blocking in firewalls by IP is a common practice however.)

Check with your email provider - or IT department if you use an in-house email solution.


The message I received is “An error occurred while sending mail. The mail server responded: Mail denied for blacklisted authenticated user (From address:
name IP: AuthenticatedID:
my email. Account owner: my domain name). Please check the message and try again.”

Can someone help me understand what is going on?


1 Like

You got a god explanation from @airwhale. Someone thinks your server has been acting as a spam relay (on purpose or from insecure practices that let others pass along spam), and/or due to overall volume of mail coming from that server, and/or messages seem to have characteristics of spam in them.

Another common cause is email forwarders. If you have forwarding to, then if is spammed, that mail server could forward that onto Yahoo. Then, Yahoo servers might see your mail IP address as relaying the spam message to their server, even though it wasn’t the originating server of the spam.

Here’s a good general article on the topic: