I have downloaded a Minecraft world from my server and I want to play it, but the commands like e.g. / gamemode 1/2/3 do not go! White jmd. Why?
Presumably you have no rights, you can in the menu (Esc, not the main menu) start the world in lan mode then it should go again
Probably because cheats are not activated. Open the world in the LAN and allow cheats, then it should work.
If you are in 1.13.x, the command is no longer / gamemode 0/1/2/3 but / gamemode survival / creative / adventure / spectator
Yes thank you for this help, but this is not