Sounds more like there is some sort of port blocking going on on your router, although it would be odd to be able to update one set of speakers, and not others. Have you checked for VPNs, work profiles, virus protection programs, etc? They might be running on the router, or on your controller device.
I’d be tempted to submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. But don’t post the resulting diagnostic number here, they get sensitive about GDPR.
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 Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.
Oh, one more thought. Which Sonos OS are you running? The PLAY:1s will run either S1 or S2. The Roams and the Era 100s require S2.
Interesting. All Sonos devices should be able to be updated, then. See my first response.
