I don’t know what browser you’re using with Windows, but if the web interface (my.tablotv.com) works through your phone’s browser but not the browser in Windows then I’d suspect problems in the Windows browser.
In Windows try clearing the cache (forget my.tablotv.com). Or try (install) a different browser (Firefox, Chrome).
Also check the Windows Firewall settings (try disabling temporarily).
I also just reinstalled windows 10 for the hell of it. Same issues are persisting. Just restarted my Tablo as well. Wondering why the webapp just fails for all of my devices and windows app just crashes on every laptop pc I have.
As long as the two devices (Tablo and PC for example) can see it other on the network shouldn’t really matter if your WiFi is or is not mesh. It’s more how the devices are configured and whether they can see it other on the network.