If you previously made purchases in the game or in other apps, the reasons could be any of the following:
1. A poor Internet connection. You need a stable Internet connection to make purchases. We recommend using Wi-Fi or 3G/4G.
2. Technical problems in the app store. All game purchases are processed by the app store the game was downloaded from. If the store is currently overloaded, there might be problems with processing your request. In this case, you need to wait a few minutes and try again.
3. Issues with the app store on your device. Rebooting your device might solve this problem.

If you haven't previously made any purchases in the game or in other apps:
1. An error in your payment information. Try deleting and re-entering your payment details.
2. The payment method isn't supported. The payment method you're using might not be supported by the store. You can find a list of supported payment methods in the corresponding sections of the user support pages for Apple, Google, and Amazon.

If you still can't make a purchase, we recommend contacting the support service of your app store.