Accepted answer
Short answer: Android may block an APK because of unknown-source settings, signing issues or Play Protect warnings.
How I check this as a player
I read the exact warning instead of forcing the install.
What it changes at the table
A block can protect the device from suspicious files.
Safety note
This site is an independent 3Patti guide. I use these answers for learning rules, comparing app claims and spotting risky wording; we do not operate real-money games, process payments, or guarantee APK safety, winnings, withdrawals or bonuses.