Hello Citizens of Dalaran,
There will be a quick realm maintenance (downtime: 5-10 minutes), in order to deploy some fixes and release The Trial of the Champion dungeon (normal and heroic).
Remember that in order keep the progression feeling you will need at least The Secrets of Ulduar 10 player achievement to be able to queue or enter to the dungeon.
If you consider there is something urgent to be reported regarding this, use the email@example.com, if it is not an urgent situation report it through our bug-tracker.
Thank you and enjoy it!