myTv+ app returns error code 101 when running on Android TV box
Looking at the decompiled code there is some error method that is called with 101. It looks like this code is only executed when the parameters sent to the app on startup are not as the app expects:

On Android TV apps are started using a different "parameter" (android.intent.category.LEANBACK_LAUNCHER) where as a regular Android app is started via android.intent.category.LAUNCHER.

I have not checked it in detail but it looks like the app tries to process the parameters and fails as it does not understand the parameter used by Android TV and then displays the 101 error message.