For approximately 10 days i have been receiving the following message when attempting to send an email message from Thunderbird: Sending of the message failed. An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: resomta-a1p-077060.sys.comcast.net resomta-a1p-077060.sys.comcast.net Excessive failed authentication, ESMTP server temporarily not available. I do not receive this message when I send directly out of Xfinity. I have temporarily disabled my anti-virus (Bitdefender) but the error message still occured. I also did a full system scan but no virus was found. The email server settings appear to be correct as well. Suggestions? Thanks in advance for your help.