I'm having trouble submitting my game. I have paid and free applications contract, I have all in-app purchases in waiting for review status, but I'm still not seeing the In-app Purchases section under the main tab (under Builds). I've tested the in-app products via sandbox users and it works. As far as I know when I'm submitting for the first time I need to submit all in-apps with this build, but I don't see the in-app section under Build section. I've tried to submit it that way and got rejected as expected.
p.s. I needed art is in place and the button "Submit for review" is visible
You don't get the In App Purchases section under the Builds in iTunesConnect.
Apple provides the reason for the rejection, kindly share it, as it help us better to solve your issue.