

This worked for me and as @Fuzies777 mentioned.... Collect all 6 codex pages and give to Hytham (the Assassin in Ravensthorpe) who tells you to speak to Reda. Reda says to read 'Hidden Ones letter' in his tent. Once read, Interact and listen to the story Reda is telling. Once he finishes you then have access again to him.... Hope works for everyone
@hello_007 Same issue... No key when doing the 'quest' and now can't get back in... just stand on top!
@gryma Same issue, Not a fish to be seen... anywhere in Norway