Starting today Thunderbird has not let me send emails from my Yahoo or gmail accounts. I get the message : "Sending of the message failed. The message could not be sent because connecting to Outgoing server (SMTP) smtp.mail.yahoo.com failed. The server may be unavailable or is refusing SMTP connections. Please verify that your Outgoing server (SMTP) settings are correct and try again." I switched outgoing servers but same results. I checked my main outgoing server and all seems OK. I went directly to Yahoo and my email accounts there work fine. So I deleted one of my Yahoo accounts from Thunderbird hoping that I could resolve the problem that way but now Thunderbird does not let me add back the account. I get the message "Thunderbird failed to find the settings for your email account " yet I believe that the settings are correct (username, email address, password, incoming and outgoing server). I'm at a loss as to what to do. Any help would be much appreciated.