FoS/PoS attunement

Hi.
I'm trying to get access to FoS/PoS but both instances show the message "This instance is closed" as I try to enter. It seems the attunement quest chain starts with Apprentice Nelphi, in Dalaran, who gives you the "Inside the Frozen Citadel" quest. But not to me.
Does anyone know the pre-requisites to get this quest?
My character is level 80 and all my items are ilvl 187 but 2 of them which are ilvl 175 and 174.
Thanks in advance.

Bruh, you need to wait some 6 months for them to open lmao

The reason FOS/POS/HOR is closed is because they are not released on Frostmourne yet. Frostmourne is a progresison server

Oh-my-god! Well, at least I know it now. Many thanks for the answer :)

Didn't think it was odd the only thing people are running is VoA, OS, and Naxx? ;P