I am having an issue where I cannot receive grid coins for doing what it asks. I would feed my dragons and collect gold but I receive nothing. I have only 1 more grid left for the legendary blade dragon and only 3 hours left. Help me please.

You can only collect coins for 8 hr windows at a time(which is dependent on your timezone) and the max amount for this quest is 600. If you aren't receiving any coins during your three allotted 8hr windows then you need to file a ticket to support: https://forums.socialpointgames.com/topic/80/how-to-report-game-problems-to-support