Apps offering real-money wagering, casino-style games, or lottery participation have to be licensed in each jurisdiction where they're offered, and geofenced so they only appear or function in those approved regions — this is one of the most heavily scrutinized categories.
A frequent trigger is a real-money gaming app expanding into a new region or state before securing that specific jurisdiction's license, relying only on its original license.
"Your app offers real money gaming but does not appear to be licensed in all regions where it is currently available, per guidelines 5.3.3 and 5.3.4."