Note that to properly reinstall an app, you would remove the app, reboot the Roku, then reinstall the app. This ensures everything is cleared out from any issues with the previous installation/authentication process.
There's no guarantee this will resolve the issue, but if you do attempt to reinstall, be sure to do all those things in that order.
Roku 2 (4210), Roku Stick (3600)
Apple TV (4th gen), Fire TV, TiVo, Android TV (MiBox)
Roku generation 1, 2, 3, & 4 boxes.
Apple TV (2nd, 3rd gen)