Hello. I am setting up my server store with Trebex. I tried to set it up so the command "dropmass 10" is sent to the server when this is purchased, but in the console, it says "Command 'dropmass 10' not found". Of course executing this command in-game works fine. Is it because Trebex doesn't have permission for this command? This works fine for the Give plugin but not this plugin.

You'd need to use the console commands, not chat commands.