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.