Are you able to wire any of your speakers directly to the router with an ethernet cable?
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:
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.
Thanks for that suggestion. I tried that on steroids. I set up a separate router and I have that on a UPS to guard against power interruptions. We have very reliable power here but it can’t hurt to eliminate one of the variables. I have not assigned IP addresses to the devices yet… Oh - there is also one other annoying bug. When I try to group the devices together I get a message “To group, make sure Living Room is connected to WiFi and is set up on this system. Duh.