spawnpoint [player] does not work

I was trying to set up a UHC feature where players will spawn right where they died (in spectator mode). This was a redstone device that worked in previous versions so after much troubleshooting i went to trying to use the command from the chat window. Using anything from @a to specific usernames resulted with "Usage: /spawnpoint [player] [<x> <y> <z>]"

the only way i managed to get spawnpoint to work was just as '/spawnpoint' which i can't do in command blocks