"Server closed" when I hit a specific chunk

Generally, the realm worked great when we first fired it up, but it's been a parade of problems for the last week.   

The most frustrating issue is that when I enter a certain part of the world the game now crashes, I need to relaunch to get back, and then when I do get back in, there's a significant amount of lost progress (even when I logged out and back in immediately before).   

Attached screenshots are the error when I get punted and then when I try to get back in.  

Avoid that chunk, you say?  It's immediately off of the coast of my base.