Just wanted to share my experience with setting up my Sonos Play 5 with an Aruba WiFi controller.
After many hours of tcpdump'ing and connecting the Sonos to wired networks (with everything working perfectly!), I found that by default, Aruba WiFi controllers (mine is a 225 running version 22.214.171.124-126.96.36.199_57496) drop broadcast & multicast traffic between attached wireless clients, which is used by the Sonos Controller app to find the Sonos.
There is a setting in the Virtual Controller under "Networks" (usually the name of the SSID you've created), WLAN Settings (click "Show Advanced options"), then "Broadcast Filtering". Mine was set to "All", and a quick change to "Disabled" + reboot, the app now found the Sonos with ease. Hope this helps someone not spend 4 hours on their Christmas morning trying to debug their brand new Sonos Play 5 ;-)