A few Ogg Vorbis audio files I uploaded in June are no longer working. They were working when I first added them to the wiki, but now if I click the play button, there's no audio, and a slash mark appears over the speaker button, almost like they're automatically muted. I've uploaded about a dozen other .ogg files more recently, and those are all still working fine. There are only three of them that currently don't work, and I have no idea why.
Any ideas on why this has happened or how to fix it?