I am trying 2 open more land on dragon city and its not letting me and my son is having the same problem can u please fix it?

Hi and I'm assuming that you're at or above the appropriate friend quota and have bought the necessary lots to allow said purchase, you should contact support: https://forums.socialpointgames.com/topic/80/how-to-report-game-problems-to-support

And please read through the helpshift as well: https://socialpoint.helpshift.com/a/dragon-city/?s=islands-habitats-buildings&f=how-do-i-expand-purchase-new-islands&l=en