That seems odd, especially without knowing what the error is. Have you tried rebooting both the router and your PLAYBAR? I used to have two PLAYBARs and both had PLAY:1s as surrounds. Granted, I added them years ago, but had no issue. 

If that doesn’t help, I’d be tempted to 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.

Did you add the new Sonos to your existing system or add them as two new systems?

As independent systems there is no way to combine them.

You can factory reset the new Sonos and then ADD them to your original system and then be able to control all of them together.

Is wifi enabled on your Playbar and Play:1’s? Even if Ethernet cabled, you need wifi too for home theatre setups. 

Thanks all for the replies. Yes, the Play 1s and Playbar had wifi enabled as they were registered. They were added as separate systems. The issue was that i could not add them as surrounds to the Playbar/Sub system.

After reading all the posts on similar issues it was normal for the Play 1s to register as separate systems. You are correct that you cannot combine them, however, the app is supposed to automatically ask to join them as surrounds to another system or to make them a stereo pair. 

Did not reboot anything.

But, this afternoon i decided to open the sonos app and the first item shown was a request to add the surrounds (same as yesterday) and this time it worked. No idea why it worked today and not yesterday. Tried maybe 10 times yesterday with 100% failure but today i try it once and it worked. All done.

Thanks all.