Exactly how long are you supposed to wait for it to time out? I've been at it for an hour. Nothing - I am just staring at a blank screen.

Kinda same here. Haven't even submitted the app yet. Completed the app build and wanted to implement IAP. Hence, add the subscriptions in App Store Connect. Implemented all the code needed to handle subscriptions from the app. Then I wanted to test Went to create sandbox users to test And BAM, nothing to see. Now I am stuck without a way to test. And the development has halted.

True. Going by the recent posts, it looks like this is a widespread issue affecting a lot of people. I even submitted a support ticket. No response yet. Hope apple takes note of this. Let's see.