everytime i open a server on 1.7.10 it crashes

Put the summary of the bug you're having here
everytime i try to join a server my minecraft 1.7.10 crashes

What I expected to happen was...:
Describe what you thought should happen here I would join the server succesfully

What actually happened was...:
Describe what happened here my minecraft crashes when I open a server

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. open a server
3. it crashes