This morning, all of a sudden, Thunderbird can't connect to my email server, which is Comcast (Xfinity). I keep getting the message "Unable to connect" and "An error occurred during connection to localhost." I have not made any changes to my account settings, and I was able to connect to the email via the Xfinity email site (although I have no connection to my local folders that way). This has come at a critical time, due to some health and family issues. How can I get this back?