So I had a slightly different problem of not being able to log in to any app where I was signing in to Verizon on my Firestick (NBC, ABC, Comedy Channel. Perhaps ESPN is included in that feature).
It happened on 3 of my firesticks - an older voice remote firestick, a new voice remote firestick and also on my new 4k firestick.
I tried the privacy setting suggestions and also moved it to different tv's. I also took the firestick, logged in to another house on a different wi-fi, and I still couldn't log in. Cleared cache, reset, restarted, unplugged and still couldn't log in. The screen would just go back to the screen showing the various providers - a round and round loop.
I found another forum that said there are updates that need to run (she said she ran an update and the screen went back to Home so she thought the updates had run, when in fact, they hadn't finished!).
I took her advice and it worked! I was able to log in to all my apps where it says "log in once to Verizon and it'll automatically log in to several other apps" or something to that effect. It allows single sign-on feature for some apps.
On your Firestick, go to Settings, My Fire TV, About, Check for updates. Run the update. Then go back and check for updates again and run. Keep doing that until there are no more updates. It may reboot several times, but don't let the Home screen fool you. Manually check for updates again.
It's supposed to run updates automatically when it detects you're not using it, but perhaps it gets stuck, or wasn't sitting idle for long enough - I'm not sure. All I know is this was the solution that finally worked for me.
