What causes my xbox to not recognize disks?
The fact that it's not a ps3 !
The number one cause for an Xbox not to recognize disks is a dirty lens or a dirty disk. My Xbox has this problem but I was able to get a CD Cleaner kit from my local electronics store for about 6$ and after I cleaned it I don't have this problem.
Check and or clean the bottom of the disk, it might be scratched try using a tissue or something very soft, if that dosent work go and buy the disk doctor it cleans and fills in minor scratches
If I were you, I would clean the disc