Odd. What does the Arc Ultra show that it is receiving as a signal?

Have you submitted a system diagnostic within 10 minutes of experiencing this problem, and called Sonos Support to discuss it? 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.

I haven’t done what you mentioned as it was my first attempt to set up the Arc Ultra. Will try that. Thank you very much. 

I have the same problem except I'm switching from Arc to Arc Ultra, and I'm still not getting any sound from my Sub and Era 300 even though they have been successfully setup in the same system under the Arc Ultra

What did Support say, when you called in? 

I am having the same issue with my arc not connecting to my surrounds. The issue occurred last month for no reason. I contacted Sonos, submitted diagnostics, rebooted and reset all speakers and the end result was to tell me that I now have to hardwire my arcs as there's a known issue with the Wi-Fi signal failing, which is BS.

Interesting, this is the first I’ve heard of an issue with the WiFi signal failing. I’d have assumed that the issue was that the radio/wifi had been turned off on the Arc. I’m glad you contacted Support, and appreciate you sharing the information here. 

I forgot how support phrased it but the speakers all work when not added in a surround set-up via wifi. They told me in order to have them work as a surround sound system again that I would need to keep it hardwired, which absolutely makes no sense to me when I've had no issues with it for over a year. 

Hi ​@antman1978 

You’ll now find a fuller explanation of your issue on your own thread:

I hope this helps.

Posting an update to the issue I had with my Arc and Surrounds:

I have to admit when I’m wrong and say that the issue was not with Sonos, it was with my router. I was able to connect with the manufacturer of the router and figure out what the issue was and disable the feature that caused the issue of my speakers not connecting in surround sound. I apologize and thank Corry P for understanding my frustrations and providing me with enough solid information that helped point me in the right direction in fixing the issue. 

I am back to loving Sonos again lol… thank you again Corry P. I appreciate all of the information that you shared with me. Tell your boss that I think you deserve a bonus $$  :)