Except as otherwise provided in this Agreement, any failure of either of the parties to comply with any obligation, covenant, agreement or condition herein may be waived by the party or parties entitled to the benefits thereof only by a written instrument signed by the party or parties granting such waiver, but such waiver or failure to insist upon strict compliance with such obligation, covenant, agreement or condition shall not operate as a waiver of, or estoppel with respect to, any subsequent or other failure.