Yesterday, after 14 days, a new version of our music app Rhythmic Vocabulary for All Instruments Vol. 1 was Rejected by the review team on Apple. This version of the app has an in-app purchase where the user can buy Vol. II within the app.

I made two mistakes when submitting the app for review:

1. I forgot to upload a in-app screenshot, which is not optional and it is said to be used in the review process only.
    
2. I did not add the In-App Purchase on the main screen for the app submission

In the email from Apple, they described generic problems with in-app purchases but they do not tell you specifically what the problem is. Apparently the most common problem is not having a restore button (or feature) for the user to retrieve the in-app purchases previously made when they re-install the app or they download a new version and, I knew that was not the problem with mine.

I wrote to apple and they promptly reply telling me to submit a new build of the app and to make sure the in-app purchases were included with the build. That meant: Add a screenshot, and add the in-app purchases that you want to include in the app (on the main page)

Now we have to wait for review for another 14 days or so.