Crashes

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here
I thought when I tried to join a server to make a single player world it should bring me to a world not a crash report
What actually happened was...:
Describe what happened here
It crashes every single time I try to make a world or join a server

Steps to Reproduce:
1. Launch the game
2. click multiplayer
3. choose a server
4. Click Join
5. Read crash report