I have two 3-way switches controlling a hallway light and purchased the HS210 to replace.  Only one of the 3-ways has the neutral (white) wire, so I only replaced that one.  The outlet had the neutral, common wire, two travelers and a previously unused ground.  I connected all of these wires to the new HS210 as provided but it is unusable. When the other 3-way switch is in the on position the HS210 doesnt power on at all and the manual does nothing (and shows offline in the app). With the other 3-way switch in the off position the HS210 powers on and connects but is not usable in the app (I get a "local only" indicator). When I press the manual button I hear it click and the light comes on for a half a second before shutting off again, and the HS210 power cycles.  I have to wait a few seconds for the 210 to come back up but pressing the manual does exactly the same thing.  I've seen videos of other people with exactly the same setup able to use the 210 with just one connected, so it should be possible for me as well.

Does anyone have ideas on this?  TIA.