Spamhaus is deprecating sbl+xbl and recommends it's new zen.spamhaus.org DNSBL

http://www.spamhaus.org/zen/

>If you are currently using sbl-xbl.spamhaus.org you can now replace
>'sbl-xbl' with 'zen' (sbl-xbl.spamhaus.org will eventually become obsolete
>and may in the future be withdrawn from service).
>
>zen.spamhaus.org should now be the only spamhaus.org DNSBL in your
>configuration. You should not use ZEN together with other Spamhaus
>blocklists or you will simply be wasting DNS queries and slowing your mail
queue.

Thanks for mentioning, I missed that one...