Read some troubleshooting techniques from the following MSKB article:
Q291614 - OL2002: How to Troubleshoot Invalid Page Faults (IPF) in the Outllib.dll File
Ignore the fact that it deal with IPF.
Trying to unweave, unwind, unravel
And piece together the past and the future,
T. S. Eliot
I have 4 users set up in Windows XP Home Edition, which is up to date (SP2). All 4 are designated as "Computer Administrator". Additional "relevant" software being used is Norton SystemWorks 2003 (Norton AV 10.0.1.13), Windows XP "firewall", SpyBot 1.2. hardware in use is a D-Link DI-604 hardware router and D-Link DSS-5+ Ethernet Switch downstream from a cable modem.
My own user account uses Outlook 2002 to access 2 different POP3 email accounts, one is the 'postmaster' account from my domain, the other is my email account with our ISP. I also use Mailwasher ver 2 to access my email account with our ISP. All other user accounts only use Outlook Express v6.0 to access their single email account with our ISP.
My problem is that POP3 access is denied when I log in after any of the other 3 users have been logged in, have used Outlook Express, and then (completely) logged off. When I log in, I am not "switching" users. If I try to use Mailwasher and/or Outlook, I get the error "connection was refused, ensure that the POP3 server is correct", or the error "unable to connect to your incoming (POP3) e-mail server. If you continue to receive this message, contact your server administrator or Internet service provider (ISP)." The problem does NOT happen if the other user has been logged in but has NOT used Outlook Express. This problem has been going on long before SP2 came out for Windows XP.
Internet browsing is not affected by this problem. The ISP's POP3 server CAN be accessed from the ISP's webmail site or mail2web.com with a browser when Outlook or Mailwasher CAN'T access it, so it is NOT an issue with the POP3 server. The ONLY way I have found to fix the POP3 access problem with my user login is to do a reboot of my PC and then I login as my user. Then access is fine. I don't do ANYTHING to the Ethernet switch, router, or cable modem.
I have tried disabling Norton AV and Windows XP firewall before launching Outlook, but it has made no difference. I tried "Repair" of the LAN and network bridge, but that made no difference, either. In the "Set Program Access and Defaults" section of "Add or Remove Programs", the Custom configuration is used and is set to "use my current ..." for all choices.
Any thoughts as to where I might look to really fix this problem, so a reboot is not required?