@maf2017 that sounds like trouble with the laser assembly. You have two different lasers, one for CD and one for DVD. Obviously the DVD laser is no longer properly working. You could try to get a commercial laser lens cleaning kit and see if that makes a difference. If not you will have to take your DVD player apart and see if you can get to the laser assembly for cleaning and /or possible replacement. To assist you further we would need the complete model number.