The device put into operation a month ago, prints out about 500 prints! It shows the error code c2557 today! I look and I see that during the installation, no protective foils were removed from the toner and developer slots. I removed them and tried manual add toner from the service mode, but after several Consecutive attempts indicate that the toner is empty and needs to be replaced, although it feels sufficient (toner is heavy). After all, TCR black shows 0% in the service mode, while the other colors are about 6%! Should the black developer change?Or drum !?