To begin with, can you perhaps briefly describe your network setup, including make/model of router.

What controller device you are using for setup and it’s operating system. Any VPN or security software running on that mobile device?

Other WiFi networks/access points/Hubs in use nearby? 

Hi, I have a BT smart hub 2 and a nighthawk mesh, I’m using the Sonos app S2 on iphone IOS. I have no VPN or security software running, and the system is set up using the BT hub. 
 

I would start by ensuring the BT smarthub firmware is updated based on this thread from last year…

Some users had to switch off their BT Hub 5Ghz WiFi adapter IIRC to get it to work with Sonos products - so it’s worth quickly exploring that thread. 

I would perhaps power off the nighthawk mesh just temporarily to ensure that its not causing you any additional issues and perhaps just concentrate on resolving any issues with the BT Superhub at this stage. HTH

This seems to be a UK issue so I should probably defer to @Ken_Griffiths.

However  if I correctly understand what a BT Hub is ..it’s actually a router/modem.  If you are also using a Nighthawk Mesh it is also broadcasting Wi-Fi. That said I assume the Nighthawk Mesh is used to extend your wifi coverage with a main and satellite nodes.

It would appear that the BT Hub should be placed in “bridge mode” to disable its wi-fi. The Nighthawk Mesh would be the sole proprietor for wi-fi coverage.

Even so Mesh networks can be problematic for Sonos and innsuch cases it’s recommended that a speaker be wired; in this instance to the main node of the Nighthawk mesh, or a Sonos Boost ($99_USD).

As I said in the beginning @Ken_Griffiths may have a better take on your issue.

Oops… @Ken_Griffiths has already chimed in 

@AjTrek1,

The setup you’ve suggested of placing the BT router either into ‘Bridge’ or even ‘Modem’ mode (if the latter is supported by BT) would be my preferred choice too and to then simply use the Nighthawk mesh for the Home network.

Then, as you also say, to run the Sonos devices over a SonosNet connection by wiring a Sonos device (not a surround or Sub) to the primary Nighthawk Hub. That is definitely the way to go with the setup, but I was trying to keep the matter simple, at least initially.

It’s clear, from the many threads on the forum here, that the BT Superhub2 router has been problematic in the past, but supposedly the more recent firmware was supposed to have fixed the SSDP multicast discovery issues that were causing the controllers on one WiFi band being unable to see Sonos devices on the other. So my hope was that a firmware update might just quickly resolve the matter. 

The SonosNet setup mentioned though, is still the way to go with the system in the longer term.

Thank you all for the input, I’ll try all suggestions and come back as soon as I’ve tried them to let you know how I get on.

Update** so I switched my nighthawks off and tried to relink and it worked first time. Thank you for your help

That infers the BT router is not in Bridge mode or router-only mode at the moment... You might want to look into that further, that’s if you plan to re-instate the nighthawk wireless mesh system.

Your BT WiFi would be switched off in either of those modes and you can resort back to using the nighthawk Hubs for your network and Home WiFi instead, which may provide you with better Home WiFi coverage (perhaps?), but in that situation, when using mesh WiFi, it’s often best to wire a single Sonos product (not a surround, or Sub) to your primary nighthawk mesh Hub/Router and run your Sonos products on their own SonosNet signal instead.

A couple of other things that goes with that SonosNet setup is to remove your WiFi credentials from the Sonos App network settings, keep the wired Sonos device at least one metre away from the wireless Hub and do not cable any Sonos devices to the nighthawk satellite Hubs.

It’s often helpful (but optional) to put each of the Sonos devices IP addresses into the routers DHCP Reservation Table to ensure that they get same IP address on (re)connection to the LAN after update/reboot etc. 

Hope that info. assists.