Sorry to hear that, I'm not sure what would be causing that. Is your mobile phone recent or old? Thanks.
I have taken a look at the official Discord of Ren'py and apparently, Android 11 has a problem of compatibility with Ren'py game builds.
But I found a solution for it on the web but it takes time, I'll apply the fix when the new version is released in October and warn you so that we can see if it works.