In XCode, when I use a subscriptionstoreview it works great, lists my products and allows me to to subscribe in TestFlight it looks identical, allowing me to select a product, but when I click the subscribe button nothing happens any help would be most appreciared

Hi, I am new to the Forum, so sorry if my question is obvious. I have developed an app which I wish to distribute via the App Store, possibly charge for the app. It talks to a REST API I have developed and host on a publicly accessible server with SSL. Will my App be accepted if it talks to my API, or do I need to make it available to everyone, including documentation etc. I assume I can still restrict access using API Keys and the like? Any help would be most appreciated Rob