DNS error. Test: "SURBL: UB-BLACK" - ORF Forums

@christopher.low: You are probably getting this DNS error because uribl.com is firewalling out the DNS server 8.8.8.8 (Google Public DNS). Most DNS Blacklists and SURBLs employ a fair use policy and servers exceeding a certain amount of queries can get banned from using the service. Due to this, we recommend that you do not use third-party DNS resolution services like Google Public DNS. There are a few other recommendations for DNS servers used with ORF, learn more here: http://vamsoft.com/support/docs/how-tos/best-practices-5.0#bp-get-dns-right

As for the email getting through, ORF will always attempt to skip the smallest possible part of email testing when an error is encountered during blacklist tests. On an issue like the above, ORF will retry the lookup with the rest of the DNS servers defined (if any) and if the lookup is still failing, it will simply go to the next operation - checking another domain, checking another SURBL, running another tests etc. Due to this, the email will not just get through for one DNS lookup failing.