I have had msvnhrn@jps.net as my email address for 27 years. With the upgrade of Thunderbird you have declared it INVALID. This is incorrect, the domain, JPS.NET, is the active property of Earthlink. I assume there are one or more domain tables in cyberspace that have the wrong information. I have been working with Earthlink, to no avail. I cannot use my Thunderbird e-mail. Mail sent to me from Thunderbird software fails. Mail sent to me from other e-mail applications, works fine. I have not been able to get any messages on Thunderbird. I am receiving messages addressed to the JPS.NET address on my Earthlink Web Mail. I assume until this problem is corrected to e-mail me you have to write to msvnhrn@earthlink.net. M. S. Van Horne