Play Protect blocks the app
Installation stops when Play Protect calls the file harmful. An unknown signature can land there too. That does not always mean the file is a virus.
- The install window has More details, or Install anyway. You can continue from there.
- In Play Store you can turn off Play Protect's install scan. Turn it back on when you are done.
- If the file came from a site you do not know, do not install it. The warning is sometimes right.
Leaving Play Protect off for good leaves the phone open.