The payment provider GDevelop is using (Stripe) accept these countries.
https://www.zoho.com/checkout/faq/payme ... tries.html
If it not that, then in GDevelop go to View -> Toggle Developer Tools -> In the developer tool click "Console" on the top and it should display an error message with red at the moment you click subscribe if there is any error. You can also filter to display errors only. Copy and paste your error message(s) from the console here if there is any.