Rekordbox USB Export Issue (macOS Mojave)

Issue: Pioneer XDJ-RX3 is not recognizing my external USB after exporting Rekordbox playlists via the Sync Manager

Workflow: Bought tracks from Beatport -> Downloaded and added tracks to USB in one folder titled "Master" -> Imported the "Master" folder to Rekordbox (now tracks show in "Collection" in Rekordbox) -> Created a new Playlist in Rekordbox and added tracks to the playlist by dragging tracks from "Collection" to the respective playlist -> Via Sync Manager I checked the "synchronize playlist with device" box and checked off the playlist to be synced and clicked the arrow to initiate sync (Note: I am getting an expert error. See attached photo) -> Double checked my USB via "Devices" and made sure the tracks from the playlist had been successfully synced -> Ejected my USB from Rekordbox -> Plugged in the USB into "slot 1" in the XDJ-RX3 (then, the XDJ’s “Source" button starts to blink so it recognizes a USB has been inserted) - Click “Source” button -> Select the “USB 1” option -> Then, blank. The screen is just blank and only says "Please select a source"

Troubleshooting Fails: -Updated by RX3's firware -Erased and reformatted by USB to MS-DOS (FAT32) -Uninstalled Rekordbox and reinstalled

Key Notes:

-I am running on MacOS Mojave 10.14.6 -Rekordbox is running 6.6.3 -All my music is downloaded straight to my -USB and kept in a single "Master" folder (no music organization done outside of Rekordbox) -The USB I am exporting the playlists to is the same USB with all the music in the "Master" folder -XDJ-RX3 does work with one USB with a playlist that I used for a prior gig

CAN SOMEONE PLEASE HELP ME TROUBLESHOOT THIS ISSUE?!!