Check your firewall and see if it blocked the new release of Thunderbird.

rollymh said

After release 31.5.0 installed on 2/25 I am no longer able to send or receive email, I get the following message when attempting to send an email (I've attached a screen image of this and the error console) "Sending of message failed. The message could not be sent because connecting to the SMTP server smtp.mail.yahoo.com failed. The server may be unavailable or is refusing SMTP connections. Please verify that your SMTP server settings are correct and try again, or contact the server administrator." When attempting to receive email I get the following: "morolly44@yahoo.com: Connecting to pop.mail.yahoo.com" Before 2/25 that would change to "logging in..." and I'd receive my email. I am able to log into my accounts on yahoo.com directly and view / send email there. On a 2nd machine using another email package but sharing the same router / internet access I was able to send and email and have it received. I've checked the settings on the two accounts. I'm at a total loss. I read that someone used system restore to go back to 31.4, but I'd rather solve this if possible. It does sound like a bug in release 31.5.0. Thanks Steve Brown

The suggestion that I turn off any firewall worked. I had made sure that the MS Windows firewall was turned off, but had left on the Norton firewall. Turning it off solved the problem, thanks.

You should not need to turn the firewall off. Just make sure Thunderbird is set to Allow. Turning the firewall off is risky.

After testing with the Norton firewall turned off I turned it back on and changed the setting as Airmail suggested to Allow. It had been on Auto and that, apparently, was the problem. Thanks much Airmail