Trying to install a caseta and it doesn't work, I think the switch itself could be effective as I have spent 3+ hours trying to fix. After trying this I went back to the old configuration and got it working so I am 100 percent sure it is wired right CURRENTLY with the existing mechanical switches in both locations.
Box one (lutron)
Black to black (common)
Blue to white
White to neutral (confirmed with multimeter to be neutral continuity to ground, was not being used by existing switch)
Red to black traveler
Green to ground
Box two (existing switch)
Black with red (common, yes the common is changing colors between boxes, I checked by wiring with the existing switches and it functions) + jumper to common
White left as is
Ground