CDJ 2000 not playing standard CDs

HI

I recently purchased a CDJ 2000 second hand, and after having used it for 2 months with the USB and DATA CDs, i decided to play a standard CD and realised it just does not read them. I tried with many CDs of mine and they all eject roughly after 10 seconds. The data CDs and DVDs with files all read fine but not the CDs i actually bought from the shop. 

Any idea why this is happening? I have also factory reset it but it did not make any difference. Am i supposed to install a software or does it mean that my optical drive is broken?

Anyone else has that issue?