A scheduled maintenance will be performed tomorrow. It starts at 5:00 a.m. and is expectected to end at 11:00 a.m. (UTC).
During this maintenance the three US servers (Tanuki, Lykan and Mocomochi) will be merged into one single server named Aibatt.
Please don’t forget to remove all your items from the vendor before the maintenance is about to start.
Learn more about the server merge by taking a look at the FAQ on the official WEBZEN forums.