Android TV removing app

I downloaded and installed a 3rd party app which was not on the app store The problem I have is that every time I turn on my TV, it gets removed and I am forced to reinstall the app I have found that after reinstalling, on occasions, when I am using the app, if the app gets closed and removed. I have turned off play protect and it still happens What is the best way to stop this from happening? ** I have sldo tried using a different installer (apk mirror installer) same outcome