The 6490 Cabel is the master router, the 7490, 73 boxes are connected via LAN as IP clients. My network is not quite trivial, I have 4 Fritz boxes distributed in the house. Neither with the iPad Air nor with the Android Tablet I was able to connect to the Roon Core, things behaved exactly as described by Martin Kögel. Tonight I was caught cold, since my FritzBox 6490 Cable has performed the firmware update to Fritz-OS 7.0.
It will be useful info to have for any other users experiencing the same issue as you
