Post the image into this forum. I see nothing at the link you provided.

It would be helpful to provide the following info.

What OS are you using ?

Menu app icon > Help > More Troubleshooting Information Under 'Mail and News Accounts. Copy all the text and past into this forum. Then tell us which of the accounts is failing to get messages.

Do you get an error message from server when it tries to connect? If yes, then tell us what it says word for word or post an image of the error.

Hope this works this time. here is the link to Paste Bin. https://pastebin.com/x3kNCV7n MAC OS Monterey Version 12.3.1 iMac 27" 2020 Act # 3 is the problem child Mail and News Accounts ID Incoming server Outgoing servers Name Connection security Authentication method Name Connection security Authentication method Default? account2 (none) Local Folders None Normal password account3 (pop3) pop.gmail.com:995 SSL/TLS OAuth2 smtp.gmail.com:465 SSL/TLS OAuth2 true account6 (imap) smtp.googlemail.com:993 SSL/TLS OAuth2 smtp.googlemail.com:465 SSL/TLS OAuth2 true account7 (imap) imap.gmail.com:993 SSL/TLS OAuth2 smtp.googlemail.com:465 SSL/TLS OAuth2 true account8 (imap) imap.gmail.com:993 SSL/TLS OAuth2 smtp.googlemail.com:465 SSL/TLS OAuth2 true

the error. ERROR with account [email protected]

                 The STAT command did not succeed. Error getting
                  message number and sizes.  Mail server pop.gmail.com 
                  responded: Invalid credentials.

hope this gets thru. Thanks, Ron

check stored passwords. Menu app icon > Preferences > Privacy & Security Passwords section Click on 'Saved Passwords' Click on 'Show Passwords'

You may see 3 lines all to do with 'User name' = the problem pop gmail address. mailbox://... smtp://.... and oath://...

If you see the mailbox://... smtp://.... lines, they are not being used. It is ok to select them and click on 'Remove'.

Check the oauth line, is the 'Username' = full email address used in the pop account or only part of it? If it is not the full email address - right click on line and select 'Edit Username' completely clear the contents and carefully type in full gmail email address, all lowercase. click on 'Close'

Exit Thunderbird so all files get updated. Wait a few moments and start Thunderbird. Report on results.

It still a problem Access the stored passwords and remove them. then restart Thunderbird and this should force a prompt by google.

Well deleting the password seems to have taken care of it. Thanks a lot Toad-Hall