When any private company is wound up and any tax, interest or penalty determined under this Act on the company for any period, whether before or in the course of or after its liquidation, cannot be recovered, then every person who was a director of such company at any time during the period for which the tax was due shall, jointly and severally, be liable for the payment of such tax, interest or penalty, unless he proves to the satisfaction of the Commissioner that such non-recovery cannot be attributed to any gross neglect, misfeasance or breach of duty on his part in relation to the affairs of the company.