Cannot get music to play on Insignia digital photo frame

I have purchased an Insignia digital photo frame for the grandparents this season and I cannot get the music to play on the frame.  I've transferred the photos I want and the music to the internal memory drive of the frame but only the pictures will play - no music.  Can you make any suggestions?  The Insignia site and paperwork are no help.  I was using music I downloaded from Itunes which sits on my IMAC.
Thanks in advance.