Can you post pictures of your setup? Many ball pythons need to feel security and clutter in their enclosures (dark hides mainly) in order to have a feeding response. Otherwise some are too stressed to eat. Awhile ago I experimented with one of my males with an awesome feeding response who had never missed a meal, by removing his hide from his enclosure. He did not eat the following week. I put the hide back, and he ate the next week lol.
Tanks with all transparent sides can also be stressful for some ball pythons, so I would cover up three sides with black paper if you could.