Nightingale Legacy Portal
I'm just starting out, I'm in my Forest Abeyance realms, and so far I've found two places (a crashed ship and a uh dome building thingy) with doors I can't pass.
I have no idea what is required to pass these barriers. This is super aggravating.
I dropped into the Gloom Site of Power after picking up a favour of soaring at a bastion next ot it. Oops. :/
Then I went to a wiki and learned more about Sites of Power than was told in-game.