Lill_pablito

So I downloaded my world from the server into Minecraft single player normally and all, then I downloaded forge 1.16.5 and world edit 1.16.5. I joined the world I had downloaded on single player and come to realize that World Edit is partially broken, every time I would type //wand it would give me an error message and although all the brush commands would appear when I type "slash" "/" although if I were to type /br sphere 5 5 it would tell me I don't have permission to type that. Does anyone know how to fix this? Because I didn't see any other posts with this exact problem.