Thunderbird now consistently fails on attempting to login to BT email. It worked fine one day and not the next. It now fails every time. It now just says "Host contacted - sending login information", then comes up with an error "Sending of password did not succeed". Nothing has been changed - no settings, nothing. I had not been anywhere near the setting but have now examined them and they are indeed exactly as they were and, having checked, are exactly as they are supposed to be. The saved username and password are as they should be and I am able to login to BT email on a browser using those credentials and send and receive email with no problems. It therefore appears that there is no issue at BT and the account has not been blocked due to too many login attempts. I have cleared cache, deleted and re-installed Thunderbird but it makes no difference. Are there any ideas as to how to fix this?