Please check if you have permission to approve the charge.
Hi @remy727,
I am the store owner, and this is a development store with the app still in the development phase. I believe I have permission to approve the charge, but maybe I need to add a credit card to test it.
Thanks for your interest!
If anyone else is wondering the same: you need to add a valid phone number and address in your dev store before you can approve a one-time charge.
Just go to Settings → General and fill in the address and mobile number.
No need to add a credit card or any other payment method.