Need help – PicFlow - photo slideshow video maker for Instagram Review

I’m new to this app but so far I haven’t been able to use any music and I don’t know how to fix it. I purchased the $2.99 version but it won’t let me pick a single song from iTunes music is keeps saying “this song is protected by DRM, please download the iTunes plus version” what in the world does that even mean?! If anyone could help I’d greatly appreciate it.
Review by sweetlissa29 on PicFlow - photo slideshow video maker for Instagram.