I WISH I KNEW! After finally getting through to a support person, I found out that two of my sensors (motion and contact) are both dead. Why? Apparently because I didn’t change the batteries when I got a ‘low battery’ notice. In my mind, ‘low battery’ means it will need to be replaced soon - but I never thought it would kill the sensors! The support person pointed out that this fact (low battery can kill device) was written about in a FAQ. I don’t believe I ever saw anything about this in the boxed literature. Why not! So folks, if you are not already aware, change your batteries when you get the low battery notice, else you can throw away your sensors! I guess this is more of a rant.
Welcome to the forums. And yes, unfortunately, this is well known around these parts. It’s a terrible design. And many of us on here have lost sensors due to this.
Oh, and BTW, if this happened within the first year, they should replace them for free under the 1 year warranty. (Or at least they used to.)