I had a paperjam, and I pulled the paper out by hardly tearing it. But unfortunately I didn’t lift up the green units at the sides of the printer back door. Now error message pops up: ’Jam at exit, Open Rear door.’ I think no bits are causing this error as the paper path is completely void of any paper. And nothing broke during this process. What is causing the problem? With opening the back and switching on/off the machine the error message still comes up.