I know that your Arc is using its 2.4Ghz adapter to connect to the LAN, as its 5Ghz adapter is reserved for other connections, but what is your Roam using here? Also what channel/channel-width is in use?

Same WiFi 2.4Ghz

Then, if not using already, try using a non-overlapping channel with a 20Mhz channel-width and see if that sorts it, if not then it maybe best to submit a Sonos system diagnostic report from within the Sonos App, note it’s reference and then contact/chat with Sonos Support Staff via this LINK and see what the Staff can perhaps suggest to resolve the matter.

The problem is the roam doesn’t show up on my app. And I don’t understand your reference to 20 mhz. I just login to my home wifi. 

You mentioned your Roam was losing connection. The 20Mhz is the channel-width of your 2.4Ghz WiFi band that you mentioned the Roam was using and the non-overlapping channel is either channel 1, 6 or channel 11 - maybe start with Ch 11 in your router configuration pages accessible at the local gateway address (or use it’s App, if available ) and then go onto set the channel-width.

All the above are settings that should be available in your router’s setup pages.

As suggested when you next have a glitch, send the diagnostic and call Sonos support with the number.