I installed some custom notifications sounds on my BLU Advance 5.5 running Android 6.0 a few months ago and they've worked fine for a really long time until when recently all my notification sounds went back to default, so I try to change back to any of the old custom sounds that I'd been using, but they won't show up in the options. My custom ringtone sounds didn't change and still work fine, but my notification sounds just won't show up.
I've tried rebooting, renaming, changing the location of the file(s), and clearing the cache, but nothing works.
I don't know what to do anymore.