lvl 80 death knight cannot be trained because death gate is bugged only for me

Sorry for bad Quality, youtube ruined it a bit : https://www.youtube.com/watch?v=f6wo...ature=youtu.be
The Problem: I'm level 80 DK (Username Samest) , today i wanted to go to my trainer up in that High Citadel so I open my portal and when I get to the place it's full of Stitches as if I am still stuck on that quest where i have to kill the big Stitch guy as a DK (so the trainers are not there), but the thing is that I did that quest because if I didn't I couldn't leave the zone.
I get worried and go to SW for help, someguy thinks I'm trolling and comes to the place with me to show how easy it is to find the trainer,we open our portals at the same time and get teleported at the same time as well, but he can't see me, I'm not in the same Dimension with him. We both leave the citadel in our flying mounts and when we leave it he was able to see me, so we try to enter it with our mounts at the same time and when we do he disappears as if he went into another dimension. As i said , the video explains it all.
Notes; This never happened to me before and i can leave the place and come back to it just as easy.