GE Smart Dimmer not working in a 3-way configuration

I don’t mean to imply that there’s something wrong with the switch; I need help figuring out if I’ve wired things incorrectly. After hooking everything up, the LED on the switch is glowing but when I try to turn the switch on/off manually or through the app, the lights don’t come on. Since I’m using a dimmer switch, I’ve confirmed that brightness is set to 100%.

I read the FAQ ([FAQ] GE 3-Way Wiring) for wiring switches in a 3-way configuration and I believe my setup is “Light between switches #1”. Note that I’m not able to remove the existing kitchen light fixture to see all the connections properly. Also, the neutral wire going to the second switch doesn’t have a black tape around it.

As instructed, I connected only the neutral and the traveler wire to the second switch and left the black one dangling for the moment. These are the before and after pics of both the switches:

Any help is appreciated

If you replaced a conventional 3-way switch, the white with black tape is NOT neutral.
Disconnect the slave switch and see if main switch works. If it does, find the right neutral and connect it to the slave.
A multi meter would help to find hot and neutral

I tried disconnecting the slave switch but the main switch still doesn’t work. The red wire seemed to be at 120V wrt the ground so I tried connecting the slave switch between the red and black wires. That didn’t seem to help either.

EDIT: Oh crap, I didn’t realize that the wiring needs to be updated at the bulb as well. If I’m reading it right then the bulb should be wired (wrt to the master switch) between load and neutral wires and the addon between the traveler and neutral. I didn’t realize that the connections were switched at the bulb as well. My bad. Also, now your statement about “white not being neutral” makes more sense.