Music-player GUI no longer playing music?

EDIT: Try using NumberValues instead. Inside each NumberValue are the song ids.

And try waiting for the sound to load first before playing it.

local CurrentSong = script:WaitForChild("CurrentSong")
local Playlist = script:WaitForChild("Playlist")
local gui = script.Parent
local MainFrame = script.Parent:WaitForChild("SwitchTeam").MainFrame1
local MuteButton = MainFrame:WaitForChild("Mute")

local SongIds = {}
for _, child in ipairs(Playlist:GetChildren()) do
    if child:IsA("NumberValue") then
        table.insert(Songs, child.Value)
    end
end

local function loadSound(sound: Sound)
    if not sound.IsLoaded then
        sound.Loaded:Wait()
    end
end

local songNumber = math.random(1, #SongIds)
local function nextSong()
    if CurrentSong.IsPlaying then
        CurrentSong:Stop()
    end

    songNumber += 1
    if songNumber > #SongIds then
        songNumber = 1
    end

    CurrentSong.TimePosition = 0
    CurrentSong.SoundId = "rbxassetid://" .. SongIds[songNumber]
    loadSound(CurrentSound)
    CurrentSong:Play()
end

CurrentSong.Ended:Connect(nextSong)

-- Start music
nextSong()

MuteButton.MouseButton1Down:Connect(function()
    if CurrentSong.Volume ~= 0 then
        CurrentSong.Volume = 0
        MuteButton.Text = "Unmute Music"
    else
        MuteButton.Text = "Mute Music"
        CurrentSong.Volume = 0.5
    end
end)

--

It's probably because of Roblox removing every audio in the Marketplace back in March 2022. This made uploading audios free but the person who uploaded the audio can only be used in their game. You can also give permission to a game to use your audio but it will also need the developer's permission.

What you can do is replace the audios you're using with the public audios (mostly uploaded by Roblox and some music companies) in the Marketplace such as Life in an Elevator (rbxassetid://1841647093) and the classic Raining Tacos (rbxassetid://142376088).