[2022] [DoR] Fast travel is unavailable as the mystery 'The Seed of Travi' was not completed

Hi,
I have an issue with Assassins Creed Valhalla-Dawn of Ragnarok.
I can not fast travel to any point, i cant acces the Atlas Map. I have return to Ravensthorp and there i can fast travel. I can save the game in both maps...just that i can not fast travel in Svartalfheim.

I observed that just after accepting the Mystery Quest, the one in wich you need to take back a hammer to his owner..but woke up in a prison( i think the quest it is called ,,The Seed of Travi,,)

. Although i have completed the mission, the mystery sign remained on the map and i think that here is the problem. Maybe someone know what is to be done here or where i shoud pay attention.
I have returnet to that castle but did not find the way back to the cell where i was imprisoned with the dwarf.
If anyone have a clue about this please help. Thank you