Music / audiobook "greyed" out

[tlpmap]

I'm new to the I-Phone world, using a 4S. Music was working OK. Downloaded an audiobook from OverDrive. Now all music titiles and audiobook chapters are visible, but "greyed" out and can't access. Any ideas what happened and how to fix. Will I have to do a restore and start over?

 

[Walkiries]

delete the grayed out song and put it back again