UR22 Mkii to Iphone 8 Issues

I cannot seem to get my Iphone 8 to recognise my Steinberg UR22 MKii. I have been able to set up the unit with the Ipad (garage band) and even with a WIndows 10 PC (Cubase AI) so I know that all the cables are working correctly. I have seen the set up on Youtube and the iPhone should handshake with the unit and a message should appear asking to turn on monitoring. This does not happen. I have deleted Garage Band on the Iphone and reinstalled but no luck there either. Can you someone suggest what I might be doing wrong.