A new contact is bouncing my emails back. It's using Sophos Antispam service and after I send them the bounce notification and attach info by another channel, now they tell me I should resolve this with my ISP

Error 550 IP is blacklisted by the Antispam engine
AFIK, the ball is on their side of the court. Am I wrong?

Any shortcut to Sophos lists other than dealing with my contact non impressive support guys? They took a week to tell me what I told them in the first place.

Thank you.

0-0

I have been retired for a while now but I used to use MX Toolbox to see where an IP or email domain is blacklisted. I would have to contact the blacklist support to resolve and they usually have an online form to fill out including steps taked to resolve the issue.

https://mxtoolbox.com/blacklists.aspx

https://mxtoolbox.com/MXLookup.aspx

Getting on an anti-spam list can be very difficult to get off of.

If you have your own domain then I would first check the lists (MXTOOLBOX, etc) to see if you are listed by domain or server or IP on many lists.
If so then that is more complicated as you have to deal with many DNSBL lists.

If only your email address and only that recipient (or others using the same spam service/filter/firewall) then you generally need to have (ask) the recipients service to delist you.

Sometimes these companies have an delisting process in the company's support website.

Other times it is the recipients own configuration that can fix it.
Hopefully, this is just an isolated case.
It may be as simple as having the recipient whitelist you.

Good Luck

If YOU host your email servers and the mail is coming from your servers/domain then it's on you. If your email is hosted by someone - it's completely on them to resolve the blacklisting.

Need more details; like DonDraper said, it depends on who controls the sending email server(s). Whenever email gets tagged as SPAM , the "sender score" is too low. In the case of blacklists, the entire domain/server that's sending email has been labeled as a spammer. It can be a PITA to be removed from some SPAM lists.

If you are running your own server, make sure it is buttoned up and not running as an “open relay”. Spammers delight in bouncing mail through open relays which eventually causes the server they are taking advantage of to get blacklisted.

We don't host our mail and I believe our ISP's mail server / our domain is bouncing back.

Not sure about the recipient but their senseless replies make me believe they don't host and have little clue on how to deal with this.

That's why I asked if I should try to solve this with my provider and get a whitelisted IP or if it's our contact on the (non) receiving end that should work it out.

Will start on my end and see how far I can make it.
Also, thank you all for the links and heads up about mxtools. Never dealt with it before and this old dog loves new tricks

0-0

If you email is hosted on a shared server, there can be dozens or more different domains all sharing your IP address with you. If *any* of them is compromised, or being used to send out SPAM, then most blacklists will block the IP address. This is because it is easy to spoof the sending domain name.

The suggestion to look yourself up in MXTOOLBOX is a good one. I would also suggest doing a reverse lookup on your IP address and see if there are a lot of others sharing your server.

You can also set up a monitor on there for free, and you'll get an email if you get on a blacklist + a weekly report.

Ultimately I had to get a dedicated VPS so I'm not sharing the IP with anyone.

Others are correct - **especially** if this is a shared IP address, then your host has to deal with shutting down the offending domain, then convincing the blacklist site that they have cleaned it up.

After going through that every month or so, I moved off shared hosting.

If, though, your IP is *not* being shared, then your server may be compromised in some way.