You wanna keep crickets as more of a treat food. What kind of CGD are you feeding? Some geckos are picky on flavor/texture. By far the flavor my geckos like the best is the Pangea Watermelon. I haven't ever had need to try this but I have heard it suggested to put a drop or two of pure honey in the food to entice them to eat. Worth a shot I guess. I've also heard it suggested to gut load the crickets with the CGD to make sure the geckos are getting the proper nutrients (if they won't eat the paste.) They don't really eat all that much though. As long as they're eating/pooping I'd say you're ok.
I hope that helps!