Well, it can be not only that, but it also needs a slow connection, download error as such or it's somewhere completely different ... There was a small space on the memory card .. see how many places you have there .... you save at all ... smart phones divide it into internal and external .. then on the phone memory or on the SD card ... if you have stored on the SD card (moved applications) then the card should be functional ... Look at the song format sometimes it appears that the songs are downloaded but your player is simply invisible, so you can't play them, just download them from google play another mp3 player ... back up all the data on the card to your computer and then format the SD card ... Sometimes just the usual restart of the phone will help. Back up all data on the card and in the phone and after a factory reset you will lose all backed up data !! backup is really necessary all applications will be fucked but don't worry you will find them on your account in google play ... ☢ ☠ ☣ ☠ ☣ ☠ ☣ ☠ ☢