Thanks for your reply!

We tried two or three different dungeons. When I go to the entrance, the Screen gets black and the message "Burial Chamber" appears. After a few seconds i'm in the world again an the game shows the message "blocked".

It also does no matter if I try to go first into the dungeon or my Friend does. When I will go into the dungeon (at first or as second) the game say always "blocked" to me.

We also killed Elikthyr a second time, but that doesn't change anything :(

Greets :)