Have a read of the self help article below. If you have not recently reset your router that would be the first call, they can often get issues with IP addressing and that can cause the sort of issues you are experiencing.
One other thing is, if possible, to connect one of the speakers directly to your router to create Sonosnet. This should be covered below.
If you are still encountering issues run a diagnostic, post the number here on this thread and call the Sonos support team for help diagnosing your individual issue.
Thank you for your answer.
Unfortunately most of the fixes requires the router to be rebooted. I can’t reset my router as this is provided by my ISP. The article didn’t give me much additional input more than reboot router, reboot speakers and restart the app. Clicking through into the relevant articles didn’t add so much.
I have assigned a static IP address to each device. After I rebooted my router I managed to connect to all of them and they are now playing. I hope that the static IP addresses fixes the issue.
If not I will try to wire one of the devices to the router and create a Sonosnet.
Tell us which ISP supplied router you have? Many are poor quality, which would explain why your devices vanish seemingly randomly. Or put it into Bridge mode connect a quality router.
I have a Sonos Arc + Sub set up. For past 5 months, they used to constantly get disconnected from the app and I’ve had many annoying moments trying to connect them. Rebooting the Sonos equipment, setting the IP address as non-private on my iphone, rebooting the router, connecting them via LAN cable - you name it and I’ve tried it. Finally figured out the problem and it had nothing to do with Sonos at all. We have a home security system (Ring) which also has a wifi extender/replicator and a SIM card as well which beams the wifi using its own hotspot when the main home-wifi is down (I have Fios and the less said about it the better). Unintentionally, we had set the Ring wifi network name same as the home wifi network. We renamed the Ring network and moved all Ring devices to its own network, and now voila, the problem is solved!
Bottom line - ensure the wifi network Sonos connects to has a unique name and not shared with any other wifi networks.