Some more details would be helpful… 

How are the devices connected to your network? Which models of sub and rears do you use?

Are they shown correctly as part of the Arcs room setup in the app?

If the Arc is connected via lan cable to the router, make sure you let the Arcs wifi turned on anyway. 

Speakers are connected by WiFi , rears are Sonos One SLs, the subwoofer is the full-size sub, the app shows they are all connected

Thx for the information… 

Are you expiring the problem both in music and in tv mode?

Most times in this case it will fix the problem, if you rebond sub and rears to the Arc. 
I recommend to disconnect them from the Arcs room in settings, restart the devices including the Arc and then bond sub and rears again to the Arc. 
A router restart also would be a good option. 

I only use it for TV , I sent in diagnostics and it is working now, I noticed on system information the ARC had WM:1 and the sub and rears had WM:3 while it was not working but after sending in diagnostics and everything working now the ARC is still WM:1 but the sub and rears now have WM2 and everything is working fine

@Mark2959 

Ok, thx for feedback… in the end some kind of self healing. WM3 is strange in your case because that only is used as wireles mode in ht setup for Era speakers as rears. 
I can imagine your diagnosis will be interesting for Sonos. Maybe you can tell the mods here about the diag number or tell it directly to support via chat or call. 

It’s important to note that both the surrounds, and the Sub, connect to the Arc, and not your router directly. This is one reason why it is important not to turn off radio/wifi on the Arc, even if it is wired to your router. The bonded devices connected to the Arc do receive proxied IP addresses from your router, through the Arc.  

My ARC is not wired to my router, I’ve had the system for a little over a year and never had this problem before, the only problem I’ve had previously and very often is my Sony Bravia OLED which in settings is set to default to external audio when powered on about 80% of the time displays a message saying external audio is not available and switches to TV speakers, to get it to work I have to turn off the TV unplug power and HDMI from the ARC, wait a few minutes then rehook up power and HDMI to the ARC then turn the TV back on and everything works fine again. Sometimes it works fine for a day or 2 or 3 after the TV is powered off and on but inevitable it happens again. Any ideas why that happens? 

Not familiar with that TV set, sorry. I’d certainly check for firmware updates, then reboot it by unplugging it from the wall for 5 minutes, which would force it to reload the OS, something that doesn’t happen when you power it down using any buttons. 

I’d also be tempted to check the HDMI cable, and the connections at both ends. You are using the Sonos provided cable, right?

Yes , using Sonos provided HDMI in eARC  ports, I check often for updates, I’m wondering if it might be miscommunication with too many devices… Sonos, Sony TV, Cable Box, I’m wondering if Cable Box might be messing up communication between Sonos and Sony TV

@Mark2959 

I don’t think other hardware causes your issues. For some reason tv manufacturers often release bad CEC programming on their tv firmware. Imo that’s the reason for many HDMI CEC communication problems. 

It’s always worth testing by having one device connected, then adding the next device, and seeing where it fails. That would give you a better than average chance of identifying which device is causing the CEC controller in the TV to not work. But usually, the devices you mention shouldn’t be an issue, unless, as @Schlumpf suggests, the implementation that one or more of them is broken. Rare, but not impossible, by any means.

There’s an issue with some Sony TVs floating around this forum about needing to turn off a serial bus setting, or something like that, in order to get the Sony fully operational. You might do a forum search for RS-232 (I think). 

I appreciate your help, I’ll keep on looking