How to get permissions in Minecraft server?

I've tried typing /op (username) in the console and typing my name in the OP section of the server folder. On both occasions it said on my server "(username) has been opped." but then when I try to use a command it says I don't have permission. (and no I did not actually type "(username)"

Brent

You need the root or admin password for that.

Fred

You probably did but make sure you spell your name exactly as is…
Example if your username is Brent, if you type /op brent. It will op lower case brent not Brent. Hope this helps

Kane