I'm trying to install a smart three-way dimmer switch to replace an older dumb three-way dimmer switch. The ending result is that the switch powers on, clicks a couple of times, and then has rapid flashing red light and not able to operate.

The old setup is a smart single-pole Kasa dimmer on the left and a dumb three-way dimmer on the right. The two switches are sharing the load line (black cable):

I tried to follow the same setup with sharing the load line and connecting to the neutral and immediately the flashing starts after the switch receives power and clicks a couple of times. Same thing happens if I connect the travelers.

Can anyone provide ideas as to what I'm doing wrong.

Thanks,

David