A Command Does Not Work

Read the response
Unknown command: check spelling and the leading 
/.
No permission: the command may require another rank or role.
Cooldown: wait for the timer rather than repeating the command.
Player not found: confirm the exact current username.
Nothing visible: close inventories and try the base help command.
Use the base command
Try 
/help, then the relevant plugin entry such as 
/lwc, 
/ar, 
/tf, 
/tc, 
/vote, or 
/heads.
Aliases can help: 
/rtp and 
/wild, 
/autorank and 
/ar, 
/tempfly and 
/tf reach the same feature families.
Rank and world restrictions
Commands can depend on rank, permission, world, region, cooldown, or current state. Ask staff to check the permission only after confirming the syntax and expected rank.
Useful report: include the exact command and complete response. Screenshots preserve details before the server buries them with fresh complaints.