Why does Acorn app not work on Apple TV ?

Try the following steps for the Apple TV 4, check whether things are working after each step where appropriate, before trying the next.

1. Check that there isn’t an update for the App, navigate to the App store > purchased, scroll down and select the app and then navigate to and select the update option (if appropriate). You may wish to have your apps update automatically (settings > apps > update automatically > on).
2. Try restarting the Apple TV (settings > system > restart)
3. Try restarting the network router.
4. Press the menu button on the remote twice to activate the app launcher, scroll left/right to locate and select the app that you are having a problem with and swipe up to close (quit) it. Relaunch the app from the menu screen to check if it is now working.
5. Try deleting it and re-installing the problematic app. There are 2 methods of deleting an app.

Select the app on the main screen and press and hold the touchpad until the app icon wobbles. Press the play/pause button and choose delete from the menu that appears.

Navigate to Settings > General > Usage > Manage Storage, scroll and select the the trash can to the right of the problematic app and choose delete from the menu that appears.

I’m not really sure if there is any difference between the two methods but there have been some suggestions that the wobble method has resulted in some app data being left behind and ultimately causing an issue when the app is re-installed.

To re-install an app navigate to the App store > purchased, scroll down and select the app and then navigate to and select the install option.