Every time I log into Thunderbird for one of my email accounts or send an email, I get an error message saying "login to server (server name) failed: retry, enter new password, cancel." My password is correct. When I click cancel, I receive new emails and can write & send new emails. When I hit send, I get the same error message i got on login, but when I click "cancel", the email does get sent & the recipient gets it. The message does not go into my sent folder, however, even though it is set to.

I have 5 other email accounts by the same mail server and they have the same settings, but they do not get the same error message. What could it be? I have updated Thunderbird, erased all the passwords and re-entered them, I have checked and rechecked the server settings. What could cause this 1 account to generate this erroneous error message? I am using Thunderbird version 38.3.0.5749 win 7 pro 64 bit Thanks, RG