My YouTube mp3 converter can't find the URL.

Hello, I used to convert music from YouTube to mp3 using this site https://youtu.be/LQ7R9zHeDy8 for a year. Today it no longer works because it tells me that the URL does not exist when I try to convert music. I tried with other sites, and it's the same, so this is very problematic. (P.S.: I tried copying and pasting the link when I clicked on share, and then realizing my failure, I tried with the link in my browser's address bar.)