[MC-50029] Command isn't working in command block

Moderator note

You have a random whitespace in the middle of the command, after the last ~5. Fixed:
/execute @e[type=Player,name=clapynick] ~ ~ ~ /fill ~5 ~-1 ~5 ~1 ~-1 ~1 stone

— [Mod] Skylinerw

If you want to prevent your future commands from not working due to whitespaces, avoid your up and down keys!

— Samuel Klumpers

When I use this command:

/execute @e[type=Player,name=clapynick] ~ ~ ~ /fill ~5 ~-1 ~5  ~1 ~-1 ~1 stone

in the chat it works, but when I put the exact same command into the command block it doesn't work, I have attached a video to this so you can see clearly whats going on. (That's only if it lets me submit it)