We started getting constantly listed on Spamhaus DBL. Every single domain we mail from is listed on the DBL. That wasn't so bad because they don't get caught up in many filters.
Now we are getting on the SBL/CSS Spamhaus lists. The majority of our domains/ IPs and almost every day. We even got a new server, new IPs, and new domains and they immediately got listed.
It sounds like it's bad emails, but we checked - sending exclusively to company emails and we have one or 2 domains that send to the same lists and do not get caught up in Spamhas (beyond the DBL of course :/)
Does anyone know how this could happen? How a domain we have NEVER sent an email on could get listed on Spamhaus DBL and how our IPs are always getting listed on CS/SBL?
We even stopped "snow shoeing" and changed to only use one IP per domain, to no avail.
--We have cleaned our email list, we have the unsub link (I am trying to implement the 'List-Unsub' within the week) and I take out abuse emails ASAP.