One iPhone does not detect the Sonos system. All others do.

I‘ve checked what is visible on the local network via an LAN scan with the Network Analyzer app. Both iPhone see the same devices and with them all Sonos speakers. Same data. No clue what the difference is.

Confirm with your Son he does NOT have a VPN installed in the phone and ensure that Settings…Sonos… Local Network access is on.

Beyond that reset the Network Settings on the iPhone, Settings…General…Transfer or Reset…Reset… Reset Network Settings.

No real answer, just questions, which may or may not be a help. 

Any chance you have a mesh network? I’m wondering if his phone is connected to another subnet than the rest. 

Also, have you simply done a hard reboot of the iPhone? This might be tied to the previous suggestion, it might not. I really can’t think of a good reason this one iPhone doesn’t connect, if it isn’t the above.

At the end of the day, I’d call Sonos Support directly to discuss it.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Edit…oh, @Belly M has some good thoughts. 

Does the Wi-Fi network happen to have the same SSID for both 2.4 GHz and 5 GHz? 
 

I’ve reserved IP addresses in the router for all Sonos devices and also for all my phones and tablets. If I happen to need to use the Forget network and have the Private Wi-Fi Address on, I’ll need to check the router. 
 

https://support.apple.com/en-us/102509

”iPhone, iPad, or iPod touch

1. Open the Settings app, then tap Wi-Fi.

2. Tap the More Info button next to a network.

3. Tap to turn Private Wi-Fi Address off or on. If your device joined the network without using a private address, a privacy warning explains why.

Thank you,  this was super helpful. Was the WiFi network privacy issue for me.  I turned it off and it worked.

Please tell is what router you are using so others can find this thread when they have the same problem with it.