My Sonos beam has been working for years and suddenly quit.

I have checked all the cables, unplugged and rebooted my router and the beam.

Sometimes I can get it working for a few minutes but then it drops out again.

It still shows up in my app and says it has a strong wifi connection. But it won’t connect to the TV or music. 
I get “can’t connect now, try again later” message when trying to group the speaker with my others.

I’m not sure what to do at this point, any suggestions?