Is the Era 300 a stand alone Speaker, part of stereo pair or used as a surround?

 used as rear surround 

I guess stereo pair means hooked to music?

my era 300’s are part of my surround system

One of the speakers works as needed. This one particular speaker only blinks a white light. I unplug it for a few minutes- nothing changes.

i press the rear button quickly, and for long presses. Still blinks white. 

Ha Ha…

It can’t be a stereo pair and used as a surround at the same time. Is it part of a stereo pair that you group to a Sonos sound bar?

The Bluetooth button on the back will not help the Era 300 connect to Wi-Fi. A blue LED means that it is connected over Bluetooth or in pairing mode when it is flashing blue, but Bluetooth is disabled when being used as a surround.

If you are not having any trouble with your other Sonos devices, I’d factory reset the missing Era 300 and add it back to your system.

You would need to select remove surrounds, then add the surrounds again when both are visible in the app.

https://support.sonos.com/en-gb/article/sonos-led-lights

https://support.sonos.com/en-gb/article/reset-your-sonos-product

If in the room with the soundbar it doesn’t show as below then they are not truly surrounds

I’m new at this- it’s part of a surround system. Arc , sub mini, 2era 300’s

When both Era 300’s were connected- that’s what my app looked like. Now it only shows 1 Era 300.

​@Bigshow Machines 

Then follow ​@Mr. T advice.

If after you get everything sorted and it happens again just unplug all components for that room. Wait 5 minutes an plug in the Arc first and let it appear in the app. Next plug in the surrounds and let them re-connect to the Arc. Last plug in the sub-mini and let reconnect to the Arc.

When used as a surround system, the Sub Mini and Era 300s connect to the Arc over a private 5GHz network.

Is there anything near the missing Era 300 that would interfere with the wireless connection between it and the Arc?