Our hallway 3-way had no neutral at one end so we put the HS210 on the other end of the hallway that had the power coming in. Neutrals all tied together, two traveler wires, live/load, and ground. We left the standard "dumb" switch at the other end of the hallway that was clearly a dead end switch with no neutral present. When we turned the breaker back on, the hall light would click on then immediately off repeatedly ever second or so. When I flipped the "dumb" switch the light would turn on like normal and the smart switch seemed to do nothing.(i.e. physically pressing button yielded no result) I obviously have something wired wrong but for the life of me I cannot figure it out. Any help you can provide would be greatly appreciated!

Thanks!