Pro V3 won't airplay

Can anyone provide info on how to airplay audio from an iPhone? I’ve determined Spotify hands off the request to some Amazon or Google cloud server to stream the iPhone selected song to the V3 (device) rather than pipe it through my phone’s app then stream via WiFi to the device like I expected. Well this has constant dropout even though signal is better than 90% quality. So I’d prefer to airplay directly to the device. When I play an mp3 file then choose airplay and pick a device it spins for 10 seconds then reports it can’t connect then that device disappears from the airplay list.
What gives?