when i log into my world the game crashes

it always takes too long to load into my world but i always thought that it was just slow internet but now when i logged into the game after a long time i started having some issues. The first time when i logged into my world it crashed after some time but now it crashes right when i finnally log into the server i tried removing some mods even tho it always worked fine w mods but nothing happened. I dont realy want to redownload the game since i have some pretty important servers on it so if someone knows how to solve this PLEASE HELP!!  thank you.