Cannot upload new content/Music won't play on Plex on Samsung TV

I have the EX2Ultra. Worked great, was happily ripping CDs and uploading content, syncing with Plex Media Server on my 2018 Samsumg TV, playing my tunes and loving it. Life interceded and I didn’t use it for about 2 or 3 months. I want to upload more content, mostly ripped CDs. When I bring up the EX2 folder with its files clearly marked with the “share” icon, I thought I could just copy and paste or drag and drop music files. Nope… won’t let me. Tried just doing a simple data file… same result.

Also when I try to play through Plex on the TV, everything shows up and I can view photos and other content, but none of my music will play. Just the dreaded “unexpected error, go to our forums” message. Of course, the Plex forums are useless.

Am I missing something here or have I forgotten how to upload content to my EX2 Ultra? Any relationship to the fact that Plex won’t play my music?

And I AM able to access the existing music on my EX2 Ultra and cast it to my Onkyo receiver wired to outdoor speakers and also cast it to a stand alone outdoor speaker out by the pool through my WiFi.