I am using RevenueCat in my iOS and Android Flutter app, for allowing the purchase of a monthly/annually subscription.

On my Sandbox environment everything works great, but for some reason, my app was rejected by Apple more than 5 times with the same RevenueCat error - Purchase Already in Progress (please see the screenshot Apple sent me, attached to this question).

I've read every relevant content online regarding this error, including StackOverflow, and most of the replies indicates it is not something in the code but rather on RevenueCat's/Apple's side.

Is there anything I can do in order to fix this error at Apple, and make them approve my app? (Or at least guide them what they should do in order for it to work?)

Thank you very much!

The RevenueCat error:

Error