Server is Exchange 2K7 w/ SP1. Server was fine for POP3s access using TCP port 995 until 01/22/2010 (for over a year without issue). Since, POP3s will not work -- "Error connection is closed." even though POP3 service was running. Restarted POP3 service and even server = no change. Set POP3 to plain text and it works over TCP port 110. Any ideas on where to troubleshoot this (i.e. any particular logs, settings, etc...)? TCP trace just shows the request receiving the "Error connection is closed. 13" during the SSL continuation. Thanks to all in advance!

What happens when you run this command from the EMS: [PS] C:\>Get-ExchangeCertificate | Where {$_.Services -like "*POP*"} | Select Subject, Services, IsSelfSigned, Status, NotAfter Does Subject return the name(s) of your Exchange Client Access server(s)? Does Status return Valid or Invalid? Does IsSelfSigned return True or False? Does NotAfter return a date in the past, for instance 01/22/2010?If it turns out that you are using a self-signed certificate (worked for over a year), and it is invalid / expired, you will need to renew it: Exchange Server 2007: Renewing the self-signed certificate http://exchangepedia.com/blog/2008/01/exchange-server-2007-renewing-self.html MCTS: Messaging | MCSE: S+M | Small Business Specialist

Hi, I agree with Mr. Smith. The issue can be caused by an invalid certificate. Put run the command and put the result here. You could also check your event log, there should be some clues, just like event ID 1102. If you're using a self-signed certificate, you maybe need to renew it. Thanks, Elvis