I recently added ubl.unsubscore.com to my email server. I only have that one and the SpamHaus (Zen) activated.
I am able to see the SpamHaus listed on DNSStuff and on SpamHaus website that the person trying to email me is not listed.
So I have to think that it is ubl.unsubscore.com list. But what domain name can I enter into the browser to check this list? www.unsubscore.com does not work. A little searching led me to lashback, but the IP is not listed there either.