Rekordbox iPhone app and CDJ NXS2 don't link

Hi,

In my DJ routine I heavily rely on my iPhone to download songs on the go in case it's asked and I think it fits the night. However, I have played out a couple of times on the NXS2 set now and I can't get my iPhone connected. The rekordbox app says it's connected but it keeps hanging in the connecting screen. The NXS2 app doesn't see a connection either in the rekordbox or usb mode. Is this a know problem and is there a solution?

I use an iPhone 7 128gb with iOS 11.2.1.