BT Mail not working in Thunderbird
My BT Mail (premium account) stopped working in Thunderbird about a month ago. I've been using it for many years without a problem, so can't understand what has changed. I'm using it on a desktop with Windows 11.
I had a long session with a tech person from BT, who couldn't find anything wrong. All the IMAP settings are correct. I have removed the saved passwords in Thunderbird and changed them via the webmail platform. I have uninstalled the account and tried to reinstall it but it won't set up the account at all now.
It works perfectly on Webmail and on my iphone so it must be something to do with Thunderbird itself.
I have thousands of emails saved so any help would be appreciated.