PD-5ANS ignoring mechanical switch in 3-way configuration

After a couple of failed attempts I'm fairly certain I've got my PD-5ANS wired up correctly with the PD-5ANS on the line side and a mechanical toggle switch on the load side.The only problem is the toggle switch doesn't seem to do anything. From what I understand the blue wire going to the PD-5ANS should be sensing when the voltage changes, but it's not. I can measure the voltage at the smart switch and see that when I toggle the mechanical switch the voltage changes, but the smart switch never seems to notice. Is it possible I messed something up when I previously wired it incorrectly? Does anyone have any other idea what could be wrong?

3-way switches are basically A/B switches. Power comes in on the "common" terminal of 1 switch, then go to the other switch on traveler A or B. At the other end, power comes in on traveler A or B and goes up to the light (switch leg) via the "common" terminal. In some cases both the power and switch leg are at the same end. The electrician has to relay power or the switch leg to the other end for the switches to work. There are a couple of ways to identify this. At one end, all 3 wires of the 3-conductor cable will be attached to the 3-way switch. You may also notice the white conductor tied to a black (either power or switch leg).

If this is the case, you should still be able to use the basic wiring instructions. However, not all white wires are neutrals and you will be limited to which end the switch can go because 1 end will not have a neutral connection.

It is not impossible but unlikely you damaged the switch. You would have heard the noise or smelled the electronics burn.

One thing that could be an issue is if the mechanical switch is a backlit or nightlight switch. If it is, the voltage won't transition far enough for the PD-5ANS to react to the change. If the mechanical switch is backlit, try changing it to a standard (non-backlit) toggle.