The antispam feature in POPcon PRO works by querying DNS-based blacklists. If a blacklist server is slow, unreachable, or no longer exists, every message will wait for a DNS timeout before proceeding.
Common causes
- The
list.dsbl.orgblacklist is no longer operational (shut down). Remove it from your blacklist settings. - Your DNS server is slow or misconfigured — use a faster DNS server.
Fix
In POPcon PRO's antispam settings, remove any blacklist servers that are no longer responding, and reduce the DNS server list to a single, fast, working DNS server.