Sir, please help me, I installed one brand new machine, after one week the customer called me because there is a message in the machine " CLEAN THE SLIT GLASS ". I checked the slit glass but no problem about it. I follow the direction on the control panel to reset it. After few days the customer called me again and the same message appear.The customer is tired for this message. Please guide me to solve this problem. Thank you and more power to all of you.