Is this a sperm plug? It was stuck in the anus of my male chameleon (1 yr old). I guessed it wasn't passing out properly with the feces. As you the see the dark region was the part that actually hanging outside of his anus and it was all dried. Initially I thought it was a piece of tissue (freak...
Sometimes they get bored with the same feeder insect. If you can, you can alternate with other insects like waxworm, dubia roach, mealworm, superworm and silkworm.
You can buy small ones with less quantity, lets say 25 small silkworms. Sellers will also give you extra in case of death during the shipment, which mostly would not happen. Silkworms can grow very fast.
Also try to monitor his weight.
By the way, your little guy is very cute.^_^
Maybe he is still trying to adapt to the new environment. Your enclosure seems relatively big to him. Some people prefer to start with smaller enclosure for smaller chams. Also monitor your humidity.
Maybe try some other feeder insects such as dubia roaches and silkworms (the best).
Dust your crickets with Calcium and vitamin D time to time. What is the temperature for his basking spot? Temperature also plays a crucial role for their appetite.