Downloaded songs have gone!

[adriangio]

Hi everyone! A few days ago most of the albums I have downloaded appeard to have none or just a few songs available offline (the show the grey symbol not the green). Some albums have no song at all downloaded whereas many others still show a couple of songs in green and the rest in grey. Why could this happen?? Thank you all!!

[adriangio]

...and i get the message "downloading..." but nothhing happens. I attach a print screen.