If you have a busy server you may exceed the free usage limits for Spamhaus, if that happens surgemail will start marking everything as spam 🙂
To fix you need to register for an account with Spamhaus and pay for the appropriate level of usage.
When you register they will give you a key: 'KEYSTRINGHERE', which you will need to insert into your g_orbs_list setting as follows:
g_orbs_list name="KEYSTRINGHERE.sbl.dq.spamhaus.net" action="stamp" stamp="Spamhaus, http://www.abuse.net/sbl.phtml?IP=||remoteip||"
You can test your rbl's with this command:
tellmail orbs_test ip.address
Note: Intermittent RBL rejections
Another possible problem is that you have multiple dns servers defined with g_dns_host, and if one of them is a free dns service (as provided by google, 1.1.1.1 etc) then those services do NOT support RBL lookups. The result will be intermittent failures. You should never use a free DNS service for your email system. Instead use your own dns server, or one provided by your network provider.