How do I sign out my TV provider on my Apple TV?

I have a 4th gen Apple TV and my software is up-to-date. I'm a Dish subscriber, and I've logged in to my account. I've tried logging in to my Dish account through the FX and Comedy Central apps, but neither will let me. (When I go to login on either app, the screen briefly flashes "Loading" then I'm taken back to the app's Settings menu, still not logged in.) I thought I might try logging out of Dish on the Apple TV. But when I go to do this (Settings > Accounts > TV Provider), the Sign Out option is greyed out, and clicking on it does nothing. How can I sign out of my Dish account on my Apple TV? Thanks