Garadget spends more time offline than online

We can do the exchange and see if replacement solves the problem. Please PM me for arrangements.

I finally installed mine last night, because it was actually warm enough to be outside for more than 5 minutes. I tested it up and down many times and even integrated with IFTTT and Google Home. Everything works great so far. However, I got a notification in the middle of the night saying that the unit was offline. I remember seeing the signal strength being pretty good when I set it up (ranges between -64dB to -71dB). I hit the reset button (the cyan light was on and it seemed to be flashing at the same rate as when it is online) this morning, but as I am writing this message, I got another offline notification.

Two Questions,
What defines “good” signal strength?
Could there be another reason why the device goes offline so freqeuently?

PS, as I finish this message, device came back online.

Device may reconnect for the variety of reasons, not just signal strength related (power quality, interference etc).
If you receive frequent offline notifications, one way to rule out some of the factors it to remove Garadget from opener (unscrew M4 holding it to the mount) and bring it closer to the router for a day or two. If notifications stop, then the issue may be related to quality of the signal.