Thanks for providing your current settings, but they are not used any more. For a rochester.rr account Spectrum state you must use the following: https://www.spectrum.net/support/internet/spectrum-email-server-settings In 'Account Settings' Edit the 'Server Settings' to use the following: * Server name: '''mail.twc.com''' * Port: '''993''' (used for imap accounts) * User name = '''your full email address''' * Connection Security: '''SSL/TLS''' * Authentication Method: '''Normal Password''' Edit the SMTP so it says: * Description: '''dcady rochchester.rr''' (means it's easier to check correct smtp is selected) * Server Name: '''mail.twc.com''' * Port: '''587''' * User name: '''full email address''' * Authentication Method: '''Normal Password''' * Connection SEcurity: '''STARTTLS''' Then Exit Thunderbird, wait a few moments for background processes to complete and then restart Thunderbird.