i can t hear some artists offline

[ramfred57]

hi my friends

sorry for my poor english

I have a windows phone, and some artists couldn t be listened by offline mode...the button "offline" is blocked. but for others, ther s no problem....i don t understand why 

[Peter__]

Are you trying to offline sync a playlist? If so, do any of the tracks it fails to download appear in the Local Files tab of your desktop Spotify?