My sony dvd player is

Try first unplugging power cable for ten minutes, so that if it is just a setting problem it reset and clears the error.
More likely you will have to do the following.

If this happens with one specific disk, then the disk is either scratched, faulty or dirty.
If disk is dirty wash it under tap water (yes under the tap) and dy completely with a soft cloth, taking care no to leave water on the disk. If disk is scratced or damaged there is nothing to do. Do not wash the CD in water if the CD has a paper sticker on it.

If the problems is with all cds, then it is a lens problem.
Try first cleaning lens with a cd cleaner. Repeat the operation a couple of times.

Here is a choice of lens cleaner kits.

If the lens cleaning cd did not work you will need to take apart your DVD by undoing screws at the bottom and removing cover.Then you access the lens pickup and clean the lens with a cotton stick and isopropyl alcohol.

In some rare case the lens pickup is faulty and must be replaced, but this is not frequent.

Thanks for using Fixya

This can be either a dirty lens or a failing optics assembly. Try opening up the top and cleaning the lens using a cotton swab and alcohol. If that fails to resolve the problem, the optics will need to be replaced. If you can post the model number, I'll get the replacement cost.

Dan