If you’ve checked to ensure the power is stable, and the cord is plugged in at both ends, your best bet is to call Sonos Support directly to discuss it.

Thanks Bruce. 
 

Had Sonos for 20 years now and have had them Shut down speakers in the past ( pair of original Sonos one which they upgraded to one sl at a discounted along with a play 5 ) but I am now seriously considering replacing Sonos with something else as this is not a problem with the speakers but a strategy from Sonos to make you upgrade to different speakers every 5 years or so. 
only had these for 3 years so I am very disappointed. 

I’m sorry you’re having such difficulty. I’ve had Sonos products for at least 19 years, and not one has failed yet. And to my knowledge, none of their speakers / sound playing devices have been shut down by Sonos, they all continue as before, using either S1 or S2. The only devices I’m aware of that have been ‘retired’ are the two remotes, the iPod 30 pin connector dock, and the BRIDGE/BOOST pair, although the latter two are still supported in software, just no longer sold. 

In your situation, I’d certainly be looking at potential power situations. Sonos devices are small computers, and as such, have a certain sensitivity to power situations and failure. And frankly, any electronic device can fail. There are several members here who have all of their Sonos devices connected to filtering/UPS style devices, just in case. 

For me, I replaced the two PLAYBARs with Arcs, gifting my old devices to family and friends, who continue to use them. Neither of them have failed, either. But I’m not familiar with this strategy to force me to purchase new devices, if I’m happy with my current devices. Certainly, if I want specific new features, but my old devices continue to function as before. In fact, I still use my original PLAY:1s and PLAY:3s. 

I’m happy in the Sonos ecosystem, recognizing its limitations, with more than 20 speakers spread across my home. I don’t have any suggestions for alternate solutions.