I have used Thunderbird for years with no problem. For the last several months, I receive the following message on outbound messages only. Additionally, this issue only occurs on my desktop computer, thunderbird works fine with my laptop: “An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: resomta-a1p-076783.sys.comcast.net resomta-a1p-076783.sys.comcast.net Excessive failed authentication, ESMTP server temporarily not available.”