I've been working with Onkyo support off and on over the past few months on the following issue and am hoping someone else with a similar issue will find this post and help me (and hopefully Onkyo) troubleshoot.
I purchased the Onkyo around a year ago, setup my Port connected to an Onkyo that supports Works with SONOS (NR686) following some youtube video... Onkyo: Settings>Hardware>Works with SONOS>Connected device - choose my Port and all works great. I turn receiver off when done using, later on I start playing something on the Port zone using my Sonos app and it turns the receiver on, sets volume correctly so it can be controlled from my sonos app. Life is good.
Sometime last fall it all stops working. I can't point my finger on the root cause, but my thoughts were: sonos S2 or other update, onkyo firmware, I swapped in a new POE switch... lots of variables around the same time.
Now if I go to Onkyo: Settings>Hardware>Works with SONOS>Connected Device it either says "SONOS CONNECT was not found" or it just spins there on searching (sometimes locking up the Onkyo all together so I to yank the power before it'll work again).
Onkyo support couldn't replicate and suggested messing with Airtime Fairness settings in the Unifi environment. no dice.
I finally found some time to bang my head against the wall on this with many combinations of:
-consumer grade netgear router instead of pfsense
-netgear unmanged switch instead of unifi
-reboot equipment in every order under the sun
-sonosNet/wifi enabled on all devices except for 1 that is both wired and wifi enabled
-wifi disabled on every device and wired only
After a few false "I got it!" celebrations, here's where I am and wonder if others can replicate.... router doesn't matter at all - pfsense isn't the issue. Switch may or may not matter. Sonos relies heavily on Spanning Tree Protocol (STP). wifi enabled/disable probably doesn't matter. The issue is how many Sonos devices you have and maybe a timeout (?) on the Onkyo/STP side.
If I unplug my unifi switch/all sonos/onkyo, then first plug in my switch, then the onkyo, then my first 5 Sonos devices... things work. I can see a list of sonos devices/IP addresses when I go to Hardware>Works with SONOS>Connected Device. When I choose my Port, I can turn off my receiver, start playing something on that zone, and it will turn on the receiver and start playing. Life is good again.
That is until I plug in the rest of my SONOS devices (combo of Amps/Plays/Soundbars/etc). Then Hardware>Works with SONOS>Connected Device goes back to SONOS CONNECT was not found, selecting that zone does not turn on receiver and set it to the correct volume.
I did also add more Sonos devices last fall too - so maybe has nothing to do with firmware (onkyo or Sonos), a new switch or anything else, and it just number of Sonos devices
My working theory is that Onkyo uses STP as well when it's trying to talk to Sonos devices. When there's 5 or less devices, it can find everything before a timeout happens (??), but more than 5 devices a timeout happens first (??). Probably why Onkyo couldn't replicate... unlikely they have more than 5 Sonos devices in their lab.
Anyone else experiencing the same or similar problem? Other ideas?