Have the speakers been working with the new Sonos App and if so, when was this?
Are you using any WiFi repeaters, extenders or EoP (powerline adapters) etc? If so, what happens if you switch off those, so that all devices connect to your main router only?

What make/model is the router you are using?

Any security software running on your mobile device, such as VPN client, firewall etc?

Yes, they were working fine last week. 
Haven’t used the system in approximately one week. 
I have 3 Bell pod signal boosters in our house. 
One router for Bell Fibre that is about a year old.   
I have had no history of this happening in the past.   

yes, I have Norton 360 running on my phone. 

Just figured it out!  
I had to switch my system. 
for whatever reason my system was listed in their twice under the same name.   
one with 0 speakers available and one with all 10 that I have.  
don’t know how that happened??   
I switched it over and it appears to be working properly now. 

I would try things connected just to the main router only and leave any WiFi boosters powered off as an initial test. If no joy there, then disable Norton on the phone temporarily tooand see if either change resolves the issue. 

See attached for multicast device discovery mDNS and SSDP - I suspect something is blocking the multicast discovery packets across your local network between your mobile App and speakers.

Ah I see you’ve sorted it - glad to hear things are now working.