blacklisted - but we are not on any list

[greg33]

Hi,

we received an email from our client and replied. We got this from your software:

...
SMTP error from remote mail server after RCPT TO:<email@email.com>:
550 5.7.0 You have been blacklisted. See http://spamauditor.org/best-practices/e ... our-users/ for more information. Protection provided by MagicSpam 2.0.18-1 http://www.magicspam.com
....

the link has no real information, just a very general description of spam ?!?

I've check on https://mxtoolbox.com/ and we are not on any know blacklist. SO what could possibly be a reason for this issue - keep in mind that the client contacted us and this was a reply to his mail.

thanks

[magicspam]

Hello greg33,

Thank you for your post.

If you follow the URL in the rejection notice, you should find detailed
information as to why your message was blocked. Based on the rejection message excerpt:

"You have been blacklisted."

means that the recipient has blacklisted your email address or a domain.

In this case, we would recommend reaching out to the recipient via alternative means and ask them to whitelist you.

We hope this information helps.