Getting This Error Message Which is "in Error"

Question

Whenever I sync my iPhone I receive the following error message box at the conclusion of the sync:
Some of the items in the iTunes library including "Drift Away" were not copied to the iPhone because the can not be played on this phone.
There's a expansion box below when opening it, identifies two songs that were purchased from the iTunes Store; the song tracks are by Uncle Kracker, Drift Away & In a Little While. The expansion box also says:
...was not copied because the file type was not supported by the iPhone.
What is strange is that the Error Box with a yellow triangular icon insert is in itself in error because I have no problem playing these tracks that were supposedly not copied on my iPhone or other iOS devices. The tracks in question are listed in my Purchased Section on the left side of my iTunes graphic display.  Both tracks are categorized as being explicit,... why, I don't know, there doesn't seem to be any explicit verbiage in the songs?
What can I do to remove the erroneous error box from appearing, the Error Box is clearly in error.

Answer 1

On your phone: Settings>General>Restrictions...are yours on? Allowed Content>Music & Podcasts>Explicit.