No matter what I try Sabre keeps blocking IP adresses from my and my users who wish to register on my blog. I can see the blocked IPs in sabre statistics and try to check them on dnsbl.info The result was that these IP addresses were not listet on this DNSBL servers. I can't find a reason why they should be blocked.
How can I figure out why an IP is blocked? Which DNSBL servers is used for sabre?