Induction cooking only works with cookware that’s magnetic and reasonably flat on the bottom — a quick test is whether a refrigerator magnet sticks firmly to the pan’s underside. A pan that has warped away from flat, stainless-clad cookware built without a magnetic layer, and aluminum or copper bases never intended for induction will all be passed over by the zone — not an error, simply the physics the element depends on.
The picture changes when cookware that has always worked stops registering, or when a zone ignores every pan put on it. Cookware is ruled out at that point and the suspect becomes the induction coil or the sensor reading it, which is a diagnostic call rather than a kitchen fix.