By default even the server owner has no admin rights. Grant them from the console.

1. Open the Console in the panel .
2. Type, without a leading slash, the exact in-game name:

op add PlayerName

3. Join and run /gamemode creative in chat to test.

To remove it: op remove PlayerName. If you see “Permission Denied”, check the name (it is case-sensitive) and have the player reconnect.

Commands

Names can change between game versions, so use /help in game for the current list.

• Moderation: /op, /kick, /ban, /unban, /whitelist, /perm, /stop
• Players: /gamemode, /give, /tp, /heal, /sudo
• World: /time, /weather, /world, /chunk, /fluid, /lighting
• Building: /pos1, /pos2, /copy, /paste, /undo, /replace, /cut, /prefab
• Everyone: /help, /spawn, /ping, /warp, /emote, /whoami