Sonos PlayBar missing

You haven’t mentioned which error messages you’re receiving from the Sonos.

At the very least, I’d suggest a network refresh/reset for the Sonos. Unplug them all from power, then reboot your router. Wait two minutes for it to load back up, then plug in your Sonos devices, starting with the PLAYBAR first, then slowly moving on to your other speakers. 

If, after that, you’re still having trouble connecting or seeing any speakers, I would call Sonos Support directly to discuss it.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.