When using the command /scoreboard teams join (teamname) @p with command blocks, the @p doesn't target any players

Put the summary of the bug you're having here

*What I expected to happen was for the command to add the nearest player to a specified team.
Describe what you thought should happen here

*What actually happened was that neither the nearest player or even any player was added to the specified team.
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. In a command block enter the command "/scoreboard teams join (teamname) @p
3. Activate the command block and you will see that no player is added to the team