My app is currently being reviewed. It is being rejected because of the error 301 (it is an "underlying error") encountered when purchasing an item through the review team. With Testflight, all purchases and restores work just fine with no such error ever occurring. I have already using 15 different sandbox account users and performed about 1000 test purchases and restores without errors. I still don't know when or why the 301 error occurs. The error only occurs when the app is in review.
In any case, after the rejection message, I looked at the product list in the App Store. I noticed that all products have a red warning label:
Then I changed the price for one of the products, which initially led to an error message. But after a second try the price change worked for one of the products, and all warning messages were gone:
Does anyone know the reason for these warning labels?
Does anyone have experience with error number 301?
I am using iOS 14.5 with the target platforms iPhone / iPodTouch and as IAP: non-consumable content hosted by Apple.