Rank 2 Completion

I need to get past Rank 2 and the only thing left is to reach level 50 as Paladin or Warlock? I’m not getting the Capstone dungeon to come up. As a rogue how do you get past this? Wasn’t a problem for Rank 1 or before when if you had 75-80% completed you could do the Capstone dungeon and move on.