Commercial plumbing service. Sewer and drain cleaning. Removed toilet in washroom 291, camera drain line found soft blockage and approximately 30 feet, pulled camera and snaked out drain, put camera down line again and found some residual paper back up. Flushed line with several times. Drain flowing well at this time. Located blockage area of piping through ceiling of first floor, was not able to check suspect wye fitting due to height in ceiling. Rest of drains in the building appear to be fine and clear of blockages.