Thunderbird is only a messenger. If you receive a message of incorrect password, that means that the server setup you provided, and the email address and password you provided, are not being accepted by the email host. Sometimes this happens because the email host (such as Gmail) requires a different password when accessed from an PC email client.

Thank you David but how do I fix problem.

Unfortunately most of the inability to connect issues that arrive post an update fall to defective antivirus or other security software. So if you are immediately post update the following may see things start working and if they do, will provide a clue as the the source. The first eliminates addons in Thunderbird primarily, but also antivirus toolbars. Both can be prone to issues post update. The second removes any number of startup programs from the operating system. Including any third party antivirus/ software firewall which may see the system begin to function correctly and sign you in. * Does Thunderbird work as expected in [[Troubleshoot Mode Thunderbird|Thunderbird troubleshooting mode]]? * Does Thunderbird work as expected with your OS started in '''[http://en.wikipedia.org/wiki/Safe_mode safe mode with Networking]'''. Instructions for each operating system: [https://support.microsoft.com/en-us/windows/start-your-pc-in-safe-mode-in-windows-92c27cff-db89-8644-1ce4-b3e5e56fe234 Windows 10/11], [https://support.microsoft.com/en-us/windows/windows-startup-settings-including-safe-mode-7f31dcea-6427-0ba0-ec1b-729a56321cd3 Windows 8], [https://support.microsoft.com/en-us/windows/advanced-startup-options-including-safe-mode-b90e7808-80b5-a291-d4b8-1a1af602b617#start-computer-safe-mode=windows-7 Windows 7], [http://support.apple.com/kb/ht1564 OSX] Note operating system safe mode requires a wired internet connection. WiFi is not available in safe mode.

Be sure to also tell is your email provider domain, e.g. Gmail. It might be that you need an app password.