All switches in multi way circuits need to be replaced by insteon devices. A video that walks through the steps of rewiring your existing 3 way switches to insteon.

Insteon Dimmer 3 Way Switches Electricians
Insteon 3 way switch wiring. Its easy to do and doesnt involve any wiring changes at all. Wiring 3 way insteon switches. Great if youre building anew but almost impossible to retrofit. Jan 29 so my setup i have a 3 way switch controlling 3 led recessed lights. Find the correct wiring for a 3 way switch in 2 minutes. Turn off power remove old switch connect insteon switch to the same terminals restore power.
Weve shown how installing an insteon switch is really straight forward. I purchased 2 insteon d dimmer switches so that i can replace both switches in the 3 way circuit. Traditional switches also use traveler wires to get electricity from one switch to the next in a multi way set up. Insteon installation circuit with 3 or more switches. Circuits with 3 or more switches are called 4 way or 5 way etc or multi way. With traditional wall switches control from multiple locations like in a long hallway requires special dedicated wiring.
I wired the switches exactly as the wiring diagram in the docs say to do and it all seems to make perfect sense. With insteon every wall switch can control every other wall switch no extra wires needed. However it flat out doesnt work.