i play on this server called the nexus made by the youtuber bajancanadian every time i die or try fighting back my minecraft crashed i ignored it for a while now but it seems that it keeps getting worse

Put the summary of the bug you're having here

What I expected to happen was...:
not sure

What actually happened was...:
when i try to fight or click my mouse many times it crashes

Steps to Reproduce:
1. get on server
2. battle someone
3.crashed and gives me a long report