i cannot put music that is not a youtube link

i don't mostly put ost on youtube, and people haven't published the music themselves, i used to put links from khinsider, but now i can't

it says provide a value in the required format but that plays the music, why is it not allowed, if it was allowed again i would add final lap music to my boom karts tracks

thank you for letting everyone know. i think there is also a way to do this if you have the direct url to the file (the link ends with .mp3, for example). if not, this is something we can look forward to.