Starting a few days ago, Thunderbird (115.10.1) has started automatically sending a login request to my two BT email accounts without waiting for me to enter a password !.
This happens immediately after opening thunderbrd and it then results in a login error. After cancelling the error messages, a banner pops up saying -
"The STAT command did not succeed. Error getting message number and sizes. Mail server mail.btinternet.com responded: Invalid command; valid commands: CAPA, DELE, LIST, LAST, NOOP, RETR, RSET, STAT, TOP, UIDL or QUIT"
Normally it shows the password entry box and either I cancel it or enter my email passwords. Now it seems to wait for a few seconds (haven't counted them yet) then must presumably send something, else the BT mail server would not reply with that strange message.