I have been using Thunderbird with my Comcast / Xfinity e-mail address for years. I can no longer send e-mails through Thunderbird. I've been working on this for months. Before I give up Thunderbird completely, I thought I'd reach out to see if anyone anywhere an help me with this. Hope so. I have reset my password multiple times and that never works. Here is the error message: An error occurred while sending mail: The mail server sent an incorrect greeting: resomta-po-02v.sys.comcast.net resomta-po-02v.sys.comcast.net Excessive failed authentication, ESMTP server temporarily not available. Thank you if you can offer any suggestions that aren't terribly confusing.