Hi,
You should also consider issues with your router : I am fighting at the moment with Beocare and Asus support for my RT-AC88U.
I have a few multiroom devices and the experience is a nightmare.... Either B&O are definetly not good at all (yet) at multiroom software or Asus have issues with B&O (and maybe other router manufacturers.)
My experience with the ASUS router is that the applications (Beomusic on IOS or Android or the new bang & olufsen app) won't work at all using the 2.4 Ghz (even with everything connected on same network, no discovering of the speakers, even if I can access them with a browser from a computer or with Chromecast). They are working on the 5 Ghz channel but sometime capricious (for exemple this morning, no way to access the M5 of the bathroom from other app than the beta bang & olufsen one on Android)
BeoCare are saying this come from the router, Asus are saying they don't filter anything on the internal network but what I can see is that nothing is working !
Maybe you have the same kind of issue with your router ?