scoreboards do not work in minecraft 1.11.4, none of the related commands in the chat or in the command blocks

steps to recreate the bug
1. in minecraft 1.11.4 invoke the commandblock
2. already having the block in the inventory, put it and open its interface and put the following command "/scoreboard objetives add muertes dummy "
3. in another block of commands enter the following command "/scoreboard objetives add jugador dummy"
4. in another block of commands enter the following command "/scoreboard objetives setdisplay sidebar muertes".
and finally
5. Enter the following command in the command block "/scoreboard objetives setdisplay belowname muertes".
in two other command blocks, put the following commands
type of command block repeat
"/testfor @p [scores=\{jugador=1}]"
type of command block pulse
"/scoreboard players add @p [scores=\{jugador=1}] muertes 1

and activate all command blocks.

Observed results:
even if all the command blocks are activated none execute the commands previously put, therefore the score board does not appear on the screen or below the player's nametag

expected results:
You should appreciate the score board on the screen counting how many deaths each player takes besides appearing under your nametag of the player only being able to be visible to the other players.
please fix the commands related to the scoreboards