Unable to package game for external use on mac

hey all , new to ue4 i have made a small game and want to package it to test on other desktops (mac)
I’ve built it the same as a previous project which seems to run fine , but this particular project just isn’t I’ve done everything to my knowledge and it just doesn’t seem to work, can anyone help direct me to the source of the problem or show me how to successfully package?

I’ve attached a screenshot of what is says when it fails?!?!?