THIRD REQUEST: IPAD not downloading files from PC (they disappeared)

[leefoo]

Plan

Premium

Country

 USA

Device

IPAD Pro

Operating System

iOS 11

My Question or Issue

 I have MP3s on my PC that Spotify doesn't have. I downloaded them into Playlists so that I could play them on my IPAD. Everything was hunky dory for some months.

But.........This past week, those files disappeared from my IPAD. I've gotten a few back, but some are stubborn and still won't download (they are in my dedicated source folder).

I even tried connecting to my PC with HDMI. No help. Additionally, on my PC, I will add these files to the playlist. They show, but when I go to another playlist and then go back, they are greyed out.

I've tried switching the download button on and off on my PC, but that also greys them out, too. But grey or not, they never show on my IPAD.

I am at my wits end.

Thx for any and all help.