Unplug all of your Sonos speakers from power for about a minute and reboot your router.

I did that twice and it still does not work.

What router are you using? Are you able to connect the Playbar directly to the router with an ethernet cable? You can also try resetting the app under App Preferences or re-installing the app. Also reboot your phone.

I have a Rockus router.

Usually this will work.

Power down ALL Sonos devices.

Reboot Router.

Reboot Controller or Controllers if you have several.

Power up ONE Sonos and wait for it to appear in your Controller.

Power up additional Sonos, one at a time. I like to wait for them to appear in my Controller but a minute between seems good enough. Make sure to power up your main speakers and wait for them to appear in the Controller BEFORE any Sub or Surround.

You normally don’t have to go that far but some setups seem to get stuck and need the full set of steps.

If everything appears and is working you might avoid the problem in the future (power fail or update/reboot) by using your Router’s DHCP settings to assign all Sonos devices a Static/Reserved IP address. Then do the power-cycle again to get everything synced on the same addresses.