Oniux- permission denied when launching firefox

I’m running Backbox linux and I have installed oniux on the system and when it got to run in the terminal oniux firefox in the terminal it said permission denied to launch firefox but when just typeing in firefox in the terminal it launch it but with out oniux how do you run oniux on Backbox with out the permission denied like oniux firefox in the terminal to use oniux with firefox?