Can't add all my tracks fom iTunes.

 I'm using the latest Trial version of Rekordbox DJ on a Pioneer Controller. iTunes is my main source. I make a new Playlist in Rekordbox, then I try to drag some tracks from my iTunes Music Library to this new playlist and it doesn't load all the selected tracks. It happens even if I try to dray tracks over individually. All the tracks are downloaded onto iTunes on my laptop, they ae not in the iTunes Cloud.

If one track from Michael Jackson Album Thriller doesn't load, none of them will. I found the same with other albums; either they all drag and load or none of them will on an album

Latest  iTunes 12.7.0.166  Rekordbox  version 5.0.1

Help....