I am trying to add 4K 60p clips (mp4) from my Nikon Z7II to a project but they won't preview in the Explorer and I can't add them to the timeline (no drag 'n drop, no right click option, etc. Also can't add to Project Media.)

I have successfully created projects with these same clips in VP 19 in the past.

I've opened and closed the program. I don't recall changing any settings. Any ideas?