it turned out the admin account I was using could apply for the capability but if granted, I had to use the organization admin account to activate the signing.

in my case, I requested multiple times but the identifier screen still shows "No Status", although I received emails saying that the permission is granted and I can use it. however, the permission is nowehere to be seen.

i saw cases, where the review was very quick but other cases where it was very slow. I wonder whether this has something to do where the company is located/registered. 2 weeks passed, I still wait any action.

How does the application backend know if the user is still subscribed to the provided product?

This is a legitimate question. I started with IAP subject recently and didnt see clear instruction/method on how to connect these accounts together. Did you find a method already?

same problem. no idea why fails.