When i put custom disc in jukebox it played custom sound but when it went through hopper it started playing disc - 11 and it can't stop what do i need to do to fix this?

Are you using the 2.0 datapack? If you run /reload the game will tell you what version you have - any 1.x version of the datapack will not work with hoppers. You can download the latest version of the app and it will generate a datapack that works with hoppers.

If you are using the 2.0 datapack, try breaking the jukebox and replacing it. Are you hearing 11 play at the same time as your custom music, or is 11 playing instead of your custom music?