In-App usage error

I have a released game which I use a plugin that handles the whole iOS in-app purchace part but, I have a user that has a problem which I haven't been able to fix. I get the following error message when getting the purchace information from apple.


Error Domain=SKErrorDomain Code=0 "(null)"


The problem I thought was that the user wasn't logged in or something like that but the person is logged in to app store.

I was wondering what might cause this specific error. Because I don't get the "Cannot connect to iTunes Store" or anything like that.


Any help would be much appreciated.