MineCraft crashes

When I try to chat in Multiplayer it crashes when I send try to send the message.

What I expected to happen was...:
I thought it would send the message and I would carry on.

What actually happened was...:
It crashed when I clicked "enter/return"

Steps to Reproduce:
1. I went online playing MineZ
2. Someone would as to team.
3. I would type "Sure" and when I clicked "enter/return" it would crash