Two Red series Dimmer 3-way not working with Association Tool

I just installed 2 red series dimmer switch and I am trying to set them up in a 3 way configuration(non smart LED light fixture) . I programmed them making sure they included with the same Security Protocol(Network Security Level : ZWave_S2_Failed), setup the Zwave Association Tool. Source vs destination were swapped to make sure I did not misunderstood the terminology. Any other things I need to check? Do I need to configure the switches as 3-way in the Device settings? I did disable the relay from the Source switch.

Thanks for your help