Try setting an ip address for it - it might be an ip address allocation issue if it’s that regular. 

I’d do it for all your Sonos, it helps a lot of folks.

Look at your router’s DHCP Settings page and it should have instructions. Only takes a couple minutes to do, then power down the Sonos, reboot the rotuer and power the Sonos back up.

Even if it doesn’t fix your issue it removes one difficult to troubleshoot issue standing between you and a true solution.

Is the Arc your only Sonos speaker or is it part of a larger system?

I have the ERA300

Sonos Arc Cutting In and Out Every Two Weeks

If your Sonos Arc disconnects every two weeks and needs a reboot, try these steps:

• Check for Software Updates: Go to the Sonos app → Settings → System Updates.

• Inspect Wi-Fi or Ethernet Connection: Ensure a stable network. Try using Ethernet instead of Wi-Fi.

• Power Check: Plug into a different outlet to rule out power issues.

• Factory Reset (Last Resort): Reset and reconfigure your Arc if the issue persists.

If the problem continues, contact Sonos Support for further assistance.

Does the Arc cut in and out when watching TV or does it happen when streaming as well?

if when watching TV with Dolby Atmos content, this could be related to an issue with some TVs and an Apple TV.

if it happens with streaming services also, you could have network issues that need to be addressed.

I use an Arc and it only cuts out for a few seconds when I watch content with Dolby Atmos.