Question about the android's dungeon

Hi there,

I'm a little bit stuck with the android's dungeon?

I have to build the android's dungeon, but it's not possible?
The task says I have to be at level 13 (which is) and that I have to start the mission "the boss of the dungeon, part 2.
How can I start this mission?

I'm now at level 14 and it's still not possible? I don't know what to do? Am I missing something?

Thank you!