#1 - Aug. 13, 2018, 11:38 p.m.
Blizzard Post
At this time, we are aware of and working to resolve an issue that is causing some players to be prevented from logging into certain high population realms. While it appears that not all high population realms are affected, the issue seems to be affecting realms such as EU-Draenor and EU-Hyjal.

This is an issue of highest priority for us, and we are working to resolve it as quickly as possible.