Einster:
There's someone who has not met the quest completion requirements, so I cannot send you.
Check the list below to see which floor you can go to.

Floor 6: Complete The Dimensional Warp, Part 1

Floor 11: Complete The Dimensional Warp, Part 2

Floor 16: Complete The Dimensional Warp, Part 3

Floor 21: Complete The Dimensional Warp, Part 4

Floor 26: Complete The Dimensional Warp, Part 5