Hooking the chains on the dragon

I'm at level 63 and I can't figure out how to get the chains on the dragon. I know where they're supposed to go and for some reason the dragon won't accept them.

Before you try to attach the chains click around the dragon. Pop ups will tell an item needs to go here. Once you find the pop ups try attaching your chains. Sometimes you have to be right on target. Hope this helps.