CD-Rs playback "format unsupported"

In the past, I have had no trouble burning and playing CD-Rs on other media (i.e. CD player, car radio). I was using the Maxell CD-R. Recently, I tried to burn more CD-Rs..some were Maxell CD-Rs and some were SONY CD-Rs. It looks like they have burned to the CD-Rs because I can play the CDs in my computer. However, when I try to play on other media, it receive an error message "format unsupported". Can someone please help me resolve this?....thanks!