Shortcut setting issues



I have a MacBook Pro and my operation system is Mojave version 10.14.3.
I’m working with Sketchup 2017 make, and I can’t set my own shortcut under shortcut setting. Whenever I type any available shortcuts, after hitting return key,
there is an error message popped up as ’ key cannot be used as shortcut’.
Can anyone help me?


cannot be used as a modifier in SU Shortcuts, but some can be set in System Prefs per application…

what keys are failing?