Yes. I had to hook it up directly through my router with an Ethernet cable and use the BeoSetup app. The Beoplay app would not work for me. 

I received two M5 today.  Had the below experience with both.

Initial setup via the Beoplay app worked to join it to my network.  The app then prompted that there was a device update.  After the update completes, or rather says that it failed, the Beoplay app can no longer communicate with the the device (Errors out), yet BeoMusic and BeoSetup can both see and interact with it without issue.  I had to finish the setup via the BeoSetup app to get Google Cast working.

Very frustrating! I'm beginning to think it's the actual Beoplay app and now the device itself that needs fixing.

I keep trying to call the help line, but I'm always too late and they're closed.

Definitely an app or firmware compatibility issue as I can stream over AirPlay, Google Cast, and Bluetooth without issue.

I'm more suspect of the app as BeoMusic and BeoSetup have no communication issues.

And suddenly after listening to music for a few hours tonight both are showing up in the Beoplay app.

yep,,, thats what I think as well. Since BeoSetup app ie has no troubles connecting