I would ignore cherrios too. Sorry but that is not really dog appropriate. Skip dinner and have some turkey dogs or cut up the Natural Balance rolls for treats. Cherrios would be incredibly boring to a dog. You need higher value rewards. Go easy on him too. Check your expectations and celebrate any little success. Like humans, he may be having an off day.
Dutch Shepherd - Ptygo (Tee-Go) de las Flores
Rescue GSD - Freyja (Husband's Dog)