the Contractor has voluntarily commenced bankruptcy, insolvency, reorganisation (other than solvent reorganisation), stay, moratorium or similar debtor-relief proceedings, or shall have become insolvent or is unable to pay its debts as they become due, or admits in writing its inability to pay its debts or makes an assignment for the benefit of its creditors (the occurrence of which in each case the Contractor is obliged to notify the Owner of immediately upon, or as early as possible before, their happening);