My PC Web app no longer works. No TV let alone no TV guide. Doesn’t show the correct recorded movies. All Firesticks with Tablo app working fine.
Which browser are you using?
Disconnect from the Tablo in the browser, and then delete the Tablo from the browser using the “X” button. See below.
The web app hasn’t changed versions for months
1.9.4 build 984 
Same on various browsers - Chrome-beta, Firefox-beta, Palemoon, MS Edge-dev, all seem to still appear to function.
If first removing your tablo from your browser doesn’t work. What changed on your PC? or with your network?