Hey Lance, the problem is not an easy one to pinpoint as there are a number of reasons this might happen...
- the songs are from Apple Music (streamed; not local)
- the songs are purchased from iTunes but not downloaded to your computer yet
- the songs are DRM-protected (typically this is only with older purchased songs from back when Apple put copy-protection on their songs)
- the file path + name of that song exceeds 255 characters
- the file is in a format which can not be imported to rekordbox