It works in Play Solo but it does not work when you actually play the game. What is the problem?
function playMusic()
game.Players:WaitForChild("Player")
if game.Players:findFirstChild("Player") ~= nil then
game.Workspace.Music:Play()
end
end
repeat wait(0.1) until game.Workspace.Music ~= nil
playMusic()
It is a local script, by the way.

2 comments
I know, but for some people the sound asset doesn't load if they lag. Thank you anyway though.
You can search preloading on the wiki and learn to prevent that.