I’m equally confused, as it should ‘just work’, so I’ve got some questions. 

Are the two PLAY:1s already set up as another room? Or are they currently not part of your Sonos system?

It’s been a few months since I re-added my PLAY:1s back to my Arc, but it worked when they were set up as another ‘room’ in the Sonos system. Since they had previously been connected to a PLAYBAR, they were already set up. I’m wondering if you need to complete the intermediate step of adding them as a separate room first…

But I’m completely guessing here. I’d certainly suggest a reboot of your router, to refresh the DHCP table, but that’s a low level of possibility. Wouldn’t hurt, but may not be the answer.

I would also recommend that you submit a system diagnostic , and call Sonos Support to discuss it, or post the diagnostic number here for a Community Moderator to pick up.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, there are more options available beyond just the diagnostic analysis.

JTMIV,

Have you declined to bond AMP to PLAYBAR? I think that the PLAY:1’s will be offered next. You may need to break up the PLAY:1 pair first.

@Bruce  yes, they are already part of the system and set up in a different room as a stereo pair. I will reboot the router and will also do a system diagnostic. Thank you for the suggestions. 
 

@buzz i did decline to bond to the amp and it just ends process and takes me back. It doesn’t then go to the Play:1. 
 

I am considering taking all devices off line and factory resetting them all as well if that makes any sense. 

I wouldn’t do a factory reset unless instructed by a Sonos rep. 

No, don’t Factory reset. This will trash your Music Library Index, all of your music service registrations, and custom setup info. In the end, Factory Reset rarely cures fundamental issues.

In 2005 I had some network issues and I Factory Reset numerous times. Once I fixed the network I haven’t been inclined to Factory Reset everything since.

If you go to “About My System” do all of your units show? Are they “WM: 0” or “WM: 1”.

You could reset just the 2 Play:1s and go from there, I set my surrounds up from "virgin" Play:1's with no issue.

@buzz Thanks for the advice. I’ll avoid a factory reset then. 
 

as for settings, everything shows WM:0

@Keithmac OK. Another good idea. 

Good news. I reset the Play:1s and this time it took. They immediately set up as surrounds and all is functional. 
 

Thanks for everyone’s help.