Why cant i buy gems in brawl stars it keeps saying that purchase failed an unknown error occurred

Hi Nam7820,

Thanks for coming to Apple Support Communities for help today with buying an in-app purchase.

There are a couple of possibilities.

Are there Screen Time restrictions: Prevent in-app purchases from the App Store?

Have you checked your payment method: If your payment method is declined in the App Store or iTunes Store?

If everything looks good, you may want to try on another Wi-Fi network or cellular data.

Have a fantastic day!