Facebook iOS SDK gives FBErrorCategoryUserCancelled for no reason?

Question

I've been rejected from the App Store since the tester was unable to login to my app with Facebook Login (I use the latest Facebook iOS SDK 3.13) They've sent me a screenshot indicating "Facebook: Login cancelled".

I've searched my app's code, and the only way this message could ever be shown is if this Error message was triggered by the Facebook SDK: "FBErrorCategoryUserCancelled".

Assuming they didn't press "Don't Allow" when the Facebook login asked for permissions, why did Apple see this message?

It seems Apple testers don't have a Facebook app, and instead SignIn from the Settings (Native) with their testing Facebook user. I've tested this method myself, with multiple real iPhone devices, and specifically on the device they claim to use, which is iPhone5s with iOS7.1. I don't see this issue.

When I've stated to them this info, they replied with: "We think that this error may occur because we don't have the Facebook app installed on our devices."

What should I do? Should I resubmit the same binary and use a Demo Facebook Account for them to use ?

Answer 1

A little bit late, but as it seems I'm not the only one who tried to handle this issue, here is what happened:

At first I thought maybe I had a bad implementation, even though I used the exact code as provided by Facebook for iOS development.

The issue was "discovered" during Apple review, and guess what... The Apple testing geniuses did press the "Don't Allow" button. I had to send them over 5 messages until they finally realized their "mistake". What a waste of time.