I think I figured out what happened, so it shouldn’t be too bad to fix in the future. Here’s the quick summary:
One of the old servers was needing to be restarted over and over and over, so a few weeks ago I tried rebuilding it and switching to a new one. Which seemed to work fine. And I recently turned off the old, poorly behaved, server. But I didn’t realize there was some special addresses I had to change over, so things were pointing to the old server instead of the new one. At first I had no clue, but some digging and it made sense. It’s not designed perfectly, but hopefully it will keep on chugging.