Clarity on why account creation would be disallowed

Hello. A group I work with received a rejection notice that we are having trouble understanding:

Your app includes an account registration feature for businesses and organizations, which is considered access to external mechanisms for purchases or subscriptions to be used in the app.

Can someone point us at a section in the app store guidelines or any other communication from Apple that will help us understand the rules around account creation?

Account creation is only mentioned twice in the apps store guidelines, once to say that we must support account delation is we support account creation (we do), and the only other mention is under remote desktop apps which does not apply to us.

The is an app used by businesses. There is a very meaningful free version that many many businesses sign up for and use on a daily basis for many years. There are no solicitations or disabled features in the app to ask free users to start paying.

In a non-opinionated way, I would by default think that Apple does want high quality, free apps for businesses available on the App Store, and it seems reasonable that businesses want to have an account to save the business data they are capturing. So I am thinking this is probably a misunderstanding, but I am trying to make sure we understand the rules and are operating within them in letter and spirit before we challenge the rejection.

Thank you in advance.

Clarity on why account creation would be disallowed
 
 
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