Blacklist Blocking

Messages from a Chinese supplier of ours from an address that is on two public blacklists (Barracuda and Sorbs) are getting blocked. These message haven’t gone into spam anywhere but are just being blocked. Are there any other blocking mechanisms on the servers? If so which blacklists do they block? Otherwise can somebody please advise what might be the problem.
BTW I have suggested that the supplier tries to get themselves removed from those blacklists.

We use an internal RBL and I had intentionally listed China Unicom ranges on it for continual amounts of spam so significant that almost no single computer could even handle logging it all. Most legitimate email doesn’t come from such ISP ranges.

Most Chinese ISP IPs are blacklisted at major RBLs. In this case you were lucky we were using our own internal so we were able to remove the listing, reluctantly but still so.

Thanks. Not at all surprised that it’s a generic problem with China mail providers.

Thanks Jarland. In this case the e-mail is coming from a bona fide PCB assembler in Shenzhen. I don’t know what options they have for e-mail hosting there. Whether it would be reasonable to suggest that they switch to a provider who isn’t public blacklisted. What do you think? Or are most of the providers in that part of the world on public blacklists?