WOD Servers down

[MiRai]

Servers are under heavy load and DDOS attacks which caused Blizzard to lower their max capacity and raised queues -- Welcome to any and every release of an expansion.

If you're having specific issues then you should seek assistance on the Blizzard Technical Support forums.

EDIT: Reddit has a great thread about all of this and here's an excerpt:

• The servers are down. It's not just you.
• The queues are long. We've all seen the screen. Many of us are sitting there right now.
• The garrisons are bugged. We know that other people are inside with you.
• The flight points are jammed. We've seen the trains of mounts.
• You drew a dick with your quest item. So did thousands of other people (and most of em posted here.)
• The queues are slow. They're slow for everyone.
• "Character not found". Yep, that's happening all over too.
• Login screens are sticking at 80-90%. I'm sitting there right now.