If your e-mail settings are exactly the same in Thunderbird on both computers, then I say that the difference may be how the VPN is set up in the two different versions of Windows.

Although I'm a Windows computer tech, I haven't had much call to set up VPNs.

To rule out Thunderbird as the problem, try creating a new Profile for testing.

Thanks for your quick response. The problem still exists. I believe it's probably with the VPN since if I turn the VPN off, Tbird works fine. Of course why my W10 works and my W7 doesn't is still anyone's guess. I've even tried different VPN servers with no luck.

Thanks again.

https://support.nordvpn.com/hc/en-us