Happened twice today. Once in town busy with enchanting, game doesn’t actually dc or crash, but all interactions stop working. I can run around but not interact. Second time, during a set dungeon, suddenly no more enemies spawn, part of the map becomes inaccessible, all timers stop working and since I was on my mighty Steed at the time, I was locked on it. Could run around the part of the dungeon that was cached, but not interact with anything or get off my high horse. Both times I force-closed the game and was greeted with this same error code on my return. Quick google gave me a workaround. In the launcher I changed region to Americas and back to Europe, and managed to continue playing. Blizz please fix!
Playing seasonal crusader on Windows 10 64bit.