Cant choose Blackrock realm (disconnected server)

Hey,

Sorry for my bad English,
About 7-10 days ago i tried to log in and it gives me the queue of the Onyxia realm. I dont really know why so i tried to change realm to Blackrock. If u chose the Blackrock realm its always disconnected. I can try and i can see the characters on the other realms but Blackrock doesnt work for me.
In my work i can log on and play Blackrock but home i cant. I tried the cache delete, i checked the realmlist but i dont rly know what to do.