You cannot see other players on multiplayer or they cant see you

I was just playing on my server with my brother and friends but they said they couldn't see me or I could not see them.

What I expected to happen was...:
Of course being able to see the other players or them seeing me.

What actually happened was...:
They couldn't see me or I couldn't see see them.

Steps to Reproduce:
1.Just join a server on multiplayer on 15w37a.
2.Teleport to another player or just look around for one.
3.You or the other player cant see the other