No fall damage

I created a ticket reporting a bug in my game, because my savegame is no longer causing damage when I fall. An administrator asked me to perform a command, but the command doesn't work, I believe because when I created my world I selected to disable the commands.

The ticket I reported the bug:

https://bugs.mojang.com/browse/MC-169188  

 

In the print:

"Comando desconhecido ou incompleto (portuguese)

In english: Unknown or incomplete command

Please, when you answer this ticket do not close it, wait for me to test and say if I could fix the problem or not.

 

Edit: Happy new year admin