Blu Ray Player is no longer playing DVDs / Bluray?

The model is a Sony BDP-S5500. A few weeks ago, I once played a burned DVD from a university library. It worked fine too, but when I put in a Bluray a few days later, the player indicated "There's no disc in it" when I hit the disc icon because it did not start to read and sound was. I thought first, the disc is broken, dirty or something… But the player does not play anything… Except for streams from Amazon Prime, Youtube or Netflix. Then I made updates and the device also indicates that it is up to date. But that did not help. I can hardly imagine that it is because of the fact that once a burned disc was inserted. Nevertheless, the coincidence is funny that just after this nothing is played anymore. I just tested again, if it works for some reason. But nothing has changed…

Does anyone know what this may still be or what else could be done?

Is broken.

Open the device and clean the laser lens. Maybe the burned DVD was dirty / dusty and has the dirt then distributed in the device…

So… Open the case, with a cotton swab moistened with isopropanol (if you do not have that, you can spit it first), gently circle it over the laser lens. Then with the dry side over it again.

If not then, either the laser is defective or a fault in the electronics…

Thanks a lot! I'll try that!

That was it! Works again perfectly!