Error Code 90002

[Geist]

Could also be a matter of the sudden increase in the number of people logging in for Patch 3.4

The server might have gotten a shock when a sudden spike of people entered into the game after the update and crashed from the sudden unexpected load.

Yep, that's what I meant by "stress", more or less. It would at least make some sense, given how populated some of the servers on the Datacentre are already. If it is a scaling problem, besides, they should be able to adjust resources so that there's a proper margin (maybe the bar was set just a tiny bit too low, or the flood of players was really that unexpected).

And... maintenance time, as you pointed out! Looks like your insight might hold true.