i go on a server and then minecraft crashs and gives a warning

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...go on server e.g hipixel
3. ...and then crashs