Hi, I have the same issue. I've removed DNSBL setting from general Email Server Settings, because this caused issues.
But now all domains give a red DNSBL in Plesk Email Security config check. Hovering over the red sign shows several spamhaus.org servers. However, when I manually check the domains and IPs at spamhaus.org, they are NOT LISTED!
So why is this DNSBL sign still red? Any help much appreciated!