Connection problems which appear suddenly are often caused by network problems, not Sonos problems.  The  typical cause is duplicate IP addresses.  These often show up after an update or power outage because a reboot requires the device to request a new IP, and the router, having lost track of current IP assignments, issues a new IP that is in use by another device.  To cure this, do the following IN THIS ORDER:

Reboot/power cycle your devices in the following order:

Modem
Router
Switches or hubs
Wired Sonos units
Wireless Sonos units
Computers/printers
Wireless devices - phones/tablets etc.

Allow each device to come back up before proceeding to the next.  Note that you can permanently prevent duplicate IP addresses by assigning an IP to each device's MAC address in the router setup.  See your router manual for details.

While you wait for a Sonos forum moderator to have time to look at your diagnostic, and just as a note of concern, what exactly do you mean when you say “connected with a bridge”?

Are you talking about some sort of bridging device as part of a mesh network? 

With that many devices in your system, I’d certainly recommend re-engaging the BOOST, wired to your base network device and not an extender or secondary device, and following the reboot process as defined above by @jgatie 

Thanks Bruce, appreciate your comments.

I tried a boost connected to the router, it made little difference whether the system was through the boost or connected to directly through the router. I did originally worry I had too many devices connected through my old nighthawk r8000 but then swapped that out and tried the boost with and without the new router which was capable of running 50-60 devices easy. No difference. While connected through the boost, I did also try changing the channel but that didn’t work…I currently have the Sonos on a separate network from the rest of my Wifi with no difference.

mark

Make sure SonosNet and your wifi are not conflicted. Set one to channel 1, 6 or 11. Set the other to one of the other, remaining, of those channels. 
 

If you are running a Bridge, other posts on these forums have said that a failing power supply can cause problems. Just use the Boost. 

The BOOST still uses your router as a DHCP device. @jgatie ‘s process does a few things, the most important is cleaning of the DHCP table, thus making sure the Sonos devices no longer have duplicate IP address. If you hadn’t done that process, then using the BOOST would have given you exactly the same results as you received, i.e. non-effective. A BOOST is by no means a silver bullet to all network issues, and network issues are not just on the wifi signal, either. 

In general, the more Sonos devices in use, the more it is recommended to use SonosNet, although by no stretch is it a requirement. It sounds as if your router is prepared for that amount of traffic, but for those of us with lesser devices, such as myself, I prefer to allow a BOOST to handle the connection to my router, which puts all Sonos traffic outside of my normal wifi traffic….but not the LAN traffic. just clears up my wifi for the various tablets, phones, computers, etc, to carry the data that they need to. 

Feel with you.

Sonos is a hell of consumer electronics, never really working

do not waste your time

I suspect the Nighthawk router is perhaps the issue in this case - I’m not familiar with that particular router, but maybe its a setting on the router like QOS/Band-Steering/Airtime Fairness needs to be switched off or IGMP Snooping needs enabling? 

Has worked fine for me for 10 years. 

Network issues - start with the basics and download a WiFi analyser and see the extent of the WiFi mess around you (becoming more and more of an issue in highly populated areas) to see which of the three channels (1/6/11} are least used. This will determine what channel to use for Sonosnet (your Boost or one speaker to be wired to your Router). What you are trying to play will affect your success with 12 speakers - streaming Flacs from your own library in my experience will need a pretty clear WiFi channel so if this is not the case consider converting to MP3 which will help. It may help to reserve IP addresses in your DHCP allocation table - it may not. Use the Boost and throw away the bridge as the Boost uses the superior Sonosnet 2 Mesh. Bear in mind that microwave ovens (yours or your neighbours) can bring the system to a grinding halt - mine does. If all else fails grouping just a few speakers in the immediate listening area may stop some of the drop outs.

The days of "Sonos can support 32 speakers playing different music in different rooms" died when WiFi became mainstream in people's homes and the glaring issues with having just three 2.4ghz channels to choose from became apparent in the urban environment.

We don’t know the layout of your system.

You could have a difficult coverage. As a diagnostic step you could wire a player to your router and move BOOST around. It is best, but not required, that this now portable BOOST is wired. Placing a wired or wireless BOOST about midway between good and poor coverage areas is usually the best approach. BOOST should be located at least two feet from other wireless devices -- especially items such as wireless access points.

Refrain from Factory Reset without further consult. Factory Reset rarely cures this sort of issue and it destroys some useful diagnostic data.