I just bought some horn worms for my veiled and this is the first I've ever offered them to him and he didn't eat them he walked right by is that because it's his first time ever seeing them?
Sometimes the worms dont move enough for them to recognize them as food. I try to hand feed them and get them to wiggle more. There are also some chameleons that just aren't interested in larvae.
Like pigglett said some chams just dont like them. My female panther Eva really just hates them I have tried both colors and she will eat one or spit it out. Then she will not touch the rest of them. Good luck try to get them to move a little also it helps.