New Files Not Appearing On WD Media Player

I have a Western Digital 3TB External Hard Drive and a WD Media Player. Lately, new files that I add onto the external hard drive do not appear on the media player. All of the previous files that were on the hard drive show up just fine on the media player and the new files appear when it’s connected to a PC. I tried resetting and restarting the media player, unplugging both devices for a while, toggling the media library on and off from the media player and removing/re-adding the new files. Nothing has changed. It’s very unusual because I’ve never encountered this issue before. If anyone has any advice, I’d be extremely grateful. Thank you.