The latest versions of thunderbird have broken password support for manual config imap server
When I install the latest two versions, the email account setup fails. There is no way to get past the "incorrect username or password" message in the account setup page. I do NOT have the wrong username OR password. This is further supported by the fact that I can use an older version of thunderbird (24.8.1) with no problems, using exactly the same account setup info as fails in the two current versions. You have a bug there, guaranteed, this is not a user RTFM issue...
Alla svar (3)
Is this a Gmail account?
No it is not. I have a couple of domains and hosting from network solutions. The server is a standard IMAP server, which I am able to access email with older versions of Thunderbird, but the newer versions complain that I have an invalid username or password. It's a bug, and not an RTFM issue...
If you think it's a bug, you can raise one at Bugzilla. https://bugzilla.mozilla.org