A while back I was having issues with my nest guard going offline consistently (like 10+ times a day). This did not coincide with my internet going offline though. I did a couple of trouble shooting things and nothing seemed to work so I did a factory reset on my nest guard. This was apparently a terrible idea because I can no longer get my nest guard to finish setting up and continues to fail when trying to connect to wifi. I am on software version, 220.127.116.11.6.
The frustrating thing is that is has to be a known issue that is just not being addressed. So much for Nest Guard being supported for at least 5 years.... Sigh..... I found multiple people who have had identical issues as me and it just sounds like nothing is being done to fix it.
The "solution" in this last post was to just send a new device which is a bit discouraging for everyone else with this issue.
I apologize for my late response and thank you for all of your patience while waiting for a reply. I definitely understand how frustrating your situation must be, and I wanted to make sure that your concern was acknowledged. Do you still need help with this issue? I know that there's been a delay in response since you posted.