App Store rejected app as pre-release software

Question

Our app just got rejected by the app store with the following explanation:

Your application is labeled as pre-release software. Pre-release or trial software cannot be accepted into the production environment and is not in compliance with the App Store Review Guidelines.

If you are interested in trial testing your app and making it available only to certain users, Ad Hoc distribution is available to broaden your user base. Information on Ad Hoc distribution is available in the iOS Developer Program User Guide.

It might be a silly question, but I cannot figure out how our app is "labeled as pre-release". Is it some flag that is set in our project or target? Or is it something which is set in iTunes Connect?

UPDATE:

We have gotten an reply from Apple and it was as I thought an misunderstanding of our business model which they have accepted now.

I have accepted Hubert's answer as it was the one which was closest to the issue, although Codo's comment (which I gave an upvote) came first.

Answer 1

Did you read App Store Review Guidelines? (Link: https://developer.apple.com/appstore/guidelines.html)
Here are some items from this document:

2.9 Apps that are "beta", "demo", "trial", or "test" versions will be rejected.
2.13 Apps that are primarily marketing materials or advertisements will be rejected.
3.2 Apps with placeholder text will be rejected.

Answer 2

This problem occurred to me once, because I made my build through the Beta version of XCODE. So just make sure you are not Beta versions of iOS SDK. Hope it helps.