Not enough information to be certain, but it sounds like one of two things. Either wifi interference in the 5Ghz range interfering with the signal between the PLAYBASE and the PLAY:1s in some manner, or possibly a duplicate IP address issue caused by your router. At the very least, I’d unplug all Sonos devices from power, then reboot the router. Give it a couple of minutes to come back up before plugging back in all the Sonos devices.
However, if neither of those possibilities work, I’d submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.
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, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.
Good advice from @Airgetlam. Another question…are you sure your Sonos is updated. An error out showing no update available usually indicates that the app and/or your speakers are not yet fully updated.
The latest Sonos app version is 15.8.1. Now here’s the tricky part… all of my speakers are the latest offering that Sonos has. Each speaker version shows 15.8 which is not uncommon for them to differ from the app version. I’m not sure what version your speakers should show but I’d suspect they shouldn’t be to from from the app version.
I suggest as another step to go to Settings > About my system to see what version the Sonos app shows as well as your speakers.
Great point, and part of that whole ‘not enough information to be certain’ aspect. ;)