in-app won't pass review for unknown reason

Hi,

I am trying to get an app approved. In app purchases say that I need to fix something without saying what needs fixing. I can't add the in-app purchases to the app review and that one does not pass because there are in-app purchases missing. How can I fix this issue? I assume that during review someone could just write whats missing but obviously they won't.

The message I received said:

One or more of your In-App Purchases has been returned for the following app:

Literally nothing else.

Regards,