In 2006 Jack Kelly Partners LLC alleged that Zegelstein (defendants) advertised that the premises was suitable for commercial use. Plaintiff was not aware that the use as represented by defendants was prohibited by the certificate of occupancy (CO), and when requesting defendants to assist in conforming the CO, plaintiff claimed defendants refused. While the purpose of the lease was for the space to be used as an office and plaintiff was prohibited from any other use, the lease also prohibited plaintiff from using the premises in violation of the CO, and the CO itself prohibited commercial use of the space. Thus, plaintiff properly raised the excuse of impossibility of performance as its ability to perform under the lease was destroyed by law. Absent defendants' willingness to alter the CO, it was impossible for plaintiff to perform its obligations under the lease. What elements must be present to prove mutual mistake? Are those elements present in these facts?