Im sure this is a simple fix but, when I export my collection from Rekordbox to Traktor none of my cover art is showing up, but if I export individual playlists into rekordbox the covert art shows up.

Traktor didn’t actually support artwork in the NML and then refuses to import it later. There are multiple complaints about this on their forum.

The solution is to import your tracks directly into Traktor first, then export from MIXO. You’ll have to clear the Traktor library first.