So, July 23, I uploaded an album to my music folder on the Synology NAS I have the Emby server on my Nvidia Shield pointing to. No issue, it shows up fine.
Cut to two days later, and I have a lot of video game music uploaded to the same NAS. I realized a day later that Emby didn't pick them up. Tried manually updating the server; it stops at around 10%. It says there's an error, but if I check my other Emby server, which is running directly off that NAS, and uses the same exact folder f