Hello Mohammad.Sarhan,
Thank you for using the Apple Support Communities. I understand you're receiving an error message when you try making a purchase.
This resource should help you If your payment method is declined in the App Store or iTunes Store:
You can change your billing information in Settings on your iPhone, iPad, or iPod touch, or in iTunes on your Mac or PC. Use a valid payment method in your country or region with money available on it. You can't select None when you have an unpaid balance or payment due.
After you update your billing information, the App Store or iTunes Store automatically attempts to charge any outstanding orders to your updated payment method.
You might also be able to use the same payment method as before if you need only to update your billing address, expiration date, or other card info. If you're outside of the United States, you might also need to contact your financial institution to allow international purchases."
There's also the possibility of an unpaid balance, which is detailed below:
On your iOS device: Go to Settings > [your name] > iTunes & App Store, then tap your Apple ID. Tap View Apple ID and sign in with your Apple ID, then tap Purchase History. (You can also view your purchase history in the App Store or iTunes Store.)
Find the unpaid purchase, which is likely at the top of the list, and tap it, then change your payment method.
You must pay for any unpaid purchases or subscriptions before requesting a refund."
If you find neither of the above possibilities cover the issue, you'll want to get in touch with Apple using this link: iTunes Store Support
I hope I've answered your question!
Enjoy the rest of your day.