1.The pod is faulty so the battery has no respond. 2.The connector between pod and battery is dirty so the electricity can't pass through. 3.The voltage of mod is below 3.2v, so that it can not fire
Reinstall the pod, or try a pod which is fine.
Check connector between pod and battery is dirty or not, clean up and then try again.
Charge it some time then try again.
The air switch is covered by seal
Look the air switch if it is covered by seal, if yes then make it fine so the pole joint (like the clips) can come out.