You are currently playing on Twintania. The housing wards for this server has not yet been unlocked. Therefor you Need to travel to another worldsever to finish the quest as it is not possible to finish it on Twintania (or Spriggan) for the moment.

You can finish the quest line with the world-visiting system but you don't really need it because you (like everyone else on this server) still won't have access before housing is released (probably in Patch 5.1 - but nothing has been confirmed yet).