From time to time, we get customers complaining about Outlook POP3/SMTP problems. 99% of the time, the customer has configured Outlook incorrectly (wrong username/password, wrong server, wrong ports, etc). Enabling Outlook logging can help you make the most of your troubleshooting session.
To turn on Outlook logging:
1. Launch Outlook.
2. Navigate to Tools > Options.
3. Click the Other tab.
4. Under the General section, click the Advanced Options button.
5. Place a checkmark in the Enable logging checkbox.
6. Click OK three times, acknowledging that the settings will take effect next time you start Outlook.
7. Restart Outlook.
8. Retry the action that was causing the problem.
Now, where to find this elusive logfile?
If you're running Outlook 2000, 2002/XP, or 2003 on Windows 2000, 2003, or XP:
C:\Documents and Settings\%username%\Local Settings\Temp\OPMLOG.LOG.
If you're running Outlook 2007 on Windows 2000, 2003, or XP:
C:\Documents and Settings\%username%\Local Settings\Temp\Outlook Logging\OPMLOG.LOG.
If you're running Outlook 2007 on Windows Vista, Windows 7, or Windows 2008:
For more information, check out the following Microsoft articles:
What is the Enable logging (troubleshooting) option?
How to enable transport logging in Outlook