yeah i did set it up on server.cfg file
Don't, put it in your command line with +rcon_password "rconpassword"
and when you do type the command in game, you need to do the following steps:
1. Make sure you've restarted if you've changed the commandline or .cfg
2. Type this in console: rcon_password "password"
3. Type this in console: rcon ulx adduser "yourname" "superadmin"
If RCON refuses you access: You have the wrong password or the RCON password is not set.