Note to the moderators: I hope I'm in the right section with this thread. Apologies if I'm not.
The title says it all, really. I found out the hard way today that for some reason, on some of my older servers, I still had NJABL configured as one of the DNS blocklists. Wikipedia says:
As of March 1, 2013, NJABL is in the process of being shut down. The DNSBL zones have been emptied. [...] As of Jan 2, 2019, the domain name njabl.org was set to expire and dns servers were switched to tucows autorenew servers which would cause any lookups by servers still not having removed the configuration to have rejections.
So if you still have NJABL in your DNSBL settings, your servers are now much more likely to reject valid messages as SPAM. To spare yourself angry calls from customers, remove NJABL from your policyd-weight.conf. It's not coming back.