App Rejected by App Store

You have to put your all In-app purchase in review as well same as you did for your application. You said your In-app purchase status is Ready To Submit. So you just need to click on that button in your In-app purchase Item. Your In- app purchase items also goes for review to Apple and It will approved along with your In-app purchase.

They have rejected because still your In-app purchase items are in Ready To Submit. You can submit it by uploading screenshot to your In-app purchase items.

Hope this help.