Customer called regarding not getting any airflow to one side of the home. Found a hard cutoff of airflow between the 1st floor office and the foyer. Tried to inspect with customers scope but could not find blockage using opening at supply register and at coil. Could not see blockage at either end. Could be a damper or could be a blockage in the duct. A hatch needs to be cut in to further inspect duct and locate blockage or closed damper. Checked static pressure above coil and measured at .33". This is higher than it should be which also indicates a duct restiriction. Air filter is washable type and would recmmend standard pleated. Also, coil is rusted and customer indicated coil froze up multiple times over the summer which could be due to airflow or refrigerant leak. Recommend finding and clearing blockage and service plan and maintenance of equipment.