We have a SBS server 2000 which is configured to retrieve mail from a mail server every 15 minutes. It was doing so until we installed a CISCO 857 ADSL router.
The following error messages are displayed in the event log at the scheduled frequency.
Event ID 12050
"POP3: Failed to check the POP3 account for <mailbox> at host POP3.POP3Server.com on port 110. The error is 10060"
Event ID 12058
"POP3: There was an error processing the RETR command. The Error is 10060"
Microsoft acknowledged the problem in the KB article http://support.microsoft.com/default.aspx?scid=kb;en-us;326523
This article suggested loading SBS sp1. I did this still no change in the situation.