setblock bug

So I Was Working On My Map FNAF3 MC And Encountered A Minecraft Bug Once Again.
Aparently I Set A command_block Somewhere, And Typed This:
/setblock -47 36 886 air
And After That, The Command Block Was Removed And It Said
"This block couldn't be placed".
I Hope You Guys Could Fix This Soon, But Its Not A Major Bug, Just A Weird Bug/Glitch. Thanks!