128.5.1? And you had no trouble with 128.5.0?

• Start Windows in safe mode with networking enabled - https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode
• Still In Windows safe mode, start Thunderbird in Troubleshoot Mode - https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird

Does problem change? Pop accounts or imap accounts?

Please post to let us know

Wayne,

first, being almost finished with my 7th decade, I'm technologically obsolete. I did get in to safe mode but nothing changed.

I'm using Windows 11 now. When in safe mode the error message I got in trying to use the url you sent was that they couldn't find mozilla.org's server.

The knology account is a Pop account. The potential problem may lie in that in checking settings there is a -1 at the end of the pop3.knology.net. pop3.knology.net is how the server is listed.

Wow is now using imax but my original wowway (c2far@wowway.net) server is still pop3 and the knology account has been pop3 for the last 30 or so years. Wow bought knology aout 10 years ago.

I tried deleting the -1 and got a new Thunderbird requiring a complete set up for that account. None of my existing in box or folders transferred to the new set up which I chose not to do.

Thanks for your help even though I was unsuccessful in resolving the problem.

Please share more on your specific concerns and I will try to assist.