Crimea missing on the diplomacy list

I've started a game as Caucasus, and want to annex Crimea. However, Crimea doesn't appear on the diplomatic screen. I've tried to enter the diplomacy window via the button, via the small yellow square on the lower right corner of the sector window and by entering diplomacy from another country's yellow peace thing, and no Crimea is to be found. I also tried using the "search" option.

Game ID: 2-418.572

Anyway, hope the rest of the world accept me invading without declaring war