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.