The system cannot read the disc. The disc format may be unsupported, or the disc may be corrupted.
Eject the disc from the system and make sure it is not dirty, scratched or damaged.
Make sure the format of the disc is supported by PlayStation 4.
Supported disc formats:
Blu-ray Disc: BD-ROM, BD-R/RE (BDAV, BDMV)
DVD: DVD-ROM, DVD-R/RW (video mode, VR mode), DVD+R/RW
Playback of the following types of discs is not supported: CD, BD-RE ver.1.0, BD-R/RE XL, DVDs that have not been finalised
If the error persists, shut down the system and reboot in safe mode. Try to rebuild the system's database using Safe Mode option 5.