My friend can't join my endgame maps

I want to help my friend level fast in endgame maps, he is around 30 level rightnow. When he try to click to my endgame map portal, game says "you don't have the required quest state".

Yesterday i was tried to enter my friends portal with 16 level char and it was working. Couldn't understand why my friend can't enter mine at 33 level.