What's wrong with my server?

Hi. I run a whitelisted, vanilla survival server. However, there has recently been a large quantity of lag in addition to my inability to log in. (I get the io.netty error after a long loading screen) My belief is that there are corrupted chunks within the world. Will someone please try to fix these? Thanks!

Download the world: https://www.mediafire.com/?7vzpctsrbasndye