when I press upload it just shows the loading icon and does nothing.
It's in .wav, 4 seconds long.

Did you give it time to load? Also, sometimes if it's 4.8 seconds or higher it won't work.

it's 4 seconds, exactly. And yes, I let it load through each time. Although it never actually LOADS lol.

Try uploading ussing a different browser

Upload progress shows on the bottom of your browser btw

Mine does the same sometimes, and I just switch browsers. Do what koooper said. Sometimes the browser will fuck it up.

Also, if you have another kiai sound in your custom folder it might be blocking a new one from replacing it.

file size?

If you've got major issues with it send me the file and I'll see if I can make it work somehow.