I didn't know it could be turned in to a king you don't belong to. I also tried while being part of a kingdom and owning land.
My problem is that it's on a 3 day timer, I thought I could just leave the quest--but it expires! so I loaded a back game and am able to finish just a few hours before the timer goes off.
If you don't finish the quest,it fails and dissappears!
Werinter,
"I played it for 26 hours without any major bugs"
that's a miracle. be appreciative for what is working.