Not sure why you didn't know it had to be hosted.
put the url in quotes ulx playsound "your:URL" - though, yes, you may have trouble doing that in console if you don't know how to escape them out.
The original post and few conversations later in thread state that you have to link to a internet URL.
Also, the file link has to end in a supported file extension of .mp3, .ogg, .pls,
Whatever you're trying to use doesn't end in one of those. (Though, it does redirect, I'd guess that Gmod http.Fetch won't allow redirects, nothing the author can do to fix that)
How do I "escape it out" then? because I'm pretty sure I've run:
bind 9 "ulx playurlsound
http://monicasnwo.site.nfoservers.com/server/music/swag.mp3"
bind 9 ulx playurlsound "
http://monicasnwo.site.nfoservers.com/server/music/swag.mp3"
And neither have worked (I'll double check). When I press the 9 after binding it, it seems to recognize the bind, but it stops at "http:" and doesn't play anything. Keep in mind this is only an issue when trying to bind. The command itself via xgui or say works fine. I've always seen this when trying to bind an http link or when I paste an http via global console. Maybe I'll post a separate post on how to accomplish this?
Anyway, it's hosted, direct link to the sound play file, ends in mp3, and file plays normally via xgui and chat so that's not the issue. It's just console recognizing the URL when the bind is run.
And I understood that it has to be an internet URL. That's not the point I was trying to make.