Email Passwords
I am running the latest Thunderbird Beta 85.0b3 (64 bit). I'm unsure when the last update occurred but on 8-9/1/21 the Plusnet Webmail server didn't recognise my password for sending email and repeated attempts to install my existing password again continued to get user or password not recognised, recieving continued OK in Thunderbird and I could both send and recieve from the webnail server itself using my existing password. My other accounts continued to work normally in Thunderbire (hotmail & live.com). I assumed this was a Plusnet problem and reported it to them and they thought there was a (their) server issue that would the a day or two to fix (that means it may be fixed tomorrow). However today I found that I could not recieve emails or send from live.com in Thunderbird and again my password is not being recognised despite repeated retries of my valid password. My password continues to work when I use Outlook to access my live.com account. Currently my hotmail.com account cntinues to work for both send and recieve in Thunderbire.
It would appear that Thunderbird is somehow either mistranmitting the passwords or not interfacing properly with both the Plusnet and Outlook servers.
Wšykne wótegrona (1)
Or your anti virus is having issues with changes to security protocols.
Given that Live and hotmail are the same thing and connect to the same servers I think the issue is not Thunderbird or neither would work.
However you are not running a released version of the software, you have a beta copy which is far more likely to have bugs. It is also far more likely to run into issues with anti virus products that monitor SSL/TLS connections.
I have no idea from your description what you did to "repeated attempts to install my existing password again" actually means. Did you try and add the account to Thunderbird again? Delete the password from the password manager or just what?
What is the exact error message you receive on sending mail? That would be a start. is it exactly the same on live? or is it a different message?
Can you log into the web mail portals for each? If you have had password issues it is common for providers to disable remote download of mail or the entire account. Check the online permissions for authorized apps with each provider.