Backed up dvd &lables

hi now i dont know why but a bit of advise to all those who backup there dvds i have had many coasters but this soloution i have tried and tested many times putting a lable on a backup dvd stops the reading in the standalone dvd player its ok on pc it will play all players are different so if you have this problem try it but i would like to know why they wont play with a dvd label on them so if anyone knows please let me no .but if anyone has trouble try without a lable trust me it does work