Safety first: Do not attempt to open the battery pack or bypass safety circuits.

Charge for extended time: Place the battery on the charger or dock and leave it for several hours, even if the indicator does not change immediately.
Check charger output: Ensure you are using the correct Samsung charger. If possible, test with another compatible charger.
Try a second battery: If another battery charges and works normally, the original battery is likely damaged from deep discharge and should be replaced.
If C14 remains after prolonged charging: The battery cells may be irreversibly damaged. Replace the battery pack with a new genuine Samsung unit.

Vacuum shows C14 and cannot start; may occur after long storage.

Possible Causes