Hi,
How old is your gecko?Is he very small?Sometimes they just need time to adjust to their new surroundings so dont worry too much. What kind of stuff are you trying him with?
What kind of bowl do you have the mealies in?Mine didnt eat for 8 days cos he couldnt see them in the dish,it was too deep as he was so small! I put a marmalade lid in there for him and put the mealies on it, and he ate them
Mine had that exact same problem for a while, she started eating better when I got her a shallower dish. She was so small, the bowl looked like a random wall in her terrarium and she didn't understand that it was hollow. Once I got a shallower one she started eating better but her appetite wasn't perfect, so I would feed her maybe one waxworm every night and her appetite skyrocketed. I don't even give her waxies anymore and she's still eating normally.
A lot of people have geckos for a week or two and they don't want to eat right away after getting a new habitat. I would give it another while to let him adjust. If he hasn't eaten after 2 weeks, maybe bring him to a vet to see if he's healthy?