A couple weeks ago I started to have Thunderbird problems with a server timeout or unable to connect. I could neither read or write messages. I've set up Thunderbird using the ports specified by my ISP (lmi.net) without fixing the problem. My provider says that I may be overloading the server for some reason, and the mail server is blocking my ISP address under the assumption that the overloading is a spam attack. I've discovered that there is another generic mail client on my PC that was apparently installed when I upgraded to Windows 10. I remember being asked for my email address when I installed Windows 10, but never thought they were asking for client email installation. Have you run across any problems like this?