When I create the mission for treasure hunt, nothing happens. No ship and no mission.
I'm on 1.01, have my own civilization.
Did you play GC3?
If not nothing happens for awhile then you'll get a popup saying you got xxx gold and you'll be able to build a new ship.
If you did play 3 then you need to verify your files and if that fails ping Schism Navigator for help
Better join the forum on Discord and post there.
If you are new Discord is more responsive to needs of new players.