Here's what I know:
I used to able to upload tracks with thumbnails about a day ago. When I upload now, it goes back to the track edit screen; no matter how many times I click "Save" it keeps going back. So I go back to my SC page and the track is there but there's no thumbnail (It's using the default thumbnail which means the thumbnail hasn't been uploaded).
I tried numerous things like:
Clear ALL browsing stuff (Cookies, history, temp, etc)
Logging off and signing back in
Trying various thumbnails with different formats, none have worked
Trying various media types, none have worked
I sign out of my main SoundCloud and decide to see if it does the same to my alternative SoundCloud... Turns out, It uploads thumbnails perfectly in my damn alt account! So it must be something wrong with my main SoundCloud which is this
. Like something wrong with the servers or something, not accepting my files.