Posted 16 April 2008 - 01:23 AM
The most usual cause of this is an incorrect user name or password being held in memory. (often due to a power spike, surge or or lag, causing corruption in the log on files.) However no matter how certain you are that you are using the correct user name and password......still double check!
As a first step its worth deleting your own user accounts in Tbird, closing down Tbird , shutting down your computer, waiting 30 seconds with a blank black screen and then restarting it. and when all required startup items have been loaded, opening Tbird and setting up your accounts again.
See you you go:
If this does not shift the incorrect log on details then you will need to uninstall Tbird, reboot and then reinstall it.