Runservice.Heartbeat only working in studio?

This code is only working in studio mode:

repeat wait() until workspace.ServerFunctions.InteractiveParts.AudioBars wait(1)
-- HEARTBEAT RENDERING
    game:GetService("RunService").Heartbeat:connect(function(step)
        local AudioBars = script.Parent.AudioBars:GetChildren()
        for i = 1, #AudioBars do
            local Visual = AudioBars[i].BackVisual.SurfaceGui.AudioVisual
            local Audio = workspace.ServerFunctions.ServerSound.ServerMusic

            --

            local BarLeft1 = (Audio.PlaybackLoudness / 22)
            if BarLeft1 <= 50 * 2 then
                Visual.BarLeft1.Size = UDim2.new(0.1,0,0,BarLeft1)
            else
                Visual.BarLeft1.Size = UDim2.new(0.1,0,0,100)
            end

            local BarLeft2 = (Audio.PlaybackLoudness / 11)
            if BarLeft2 <= 50 * 2 then
                Visual.BarLeft2.Size = UDim2.new(0.1,0,0,BarLeft2)
            else
                Visual.BarLeft2.Size = UDim2.new(0.1,0,0,100)
            end

            local BarMid = (Audio.PlaybackLoudness / 5)
            if BarMid <= 50 * 2 then
                Visual.BarMid.Size = UDim2.new(0.1,0,0,BarMid)
            else
                Visual.BarMid.Size = UDim2.new(0.1,0,0,100)
            end

            local BarRight1 = (Audio.PlaybackLoudness / 8)
            if BarRight1 <= 50 * 2 then
                Visual.BarRight1.Size = UDim2.new(0.1,0,0,BarRight1)
            else
                Visual.BarRight1.Size = UDim2.new(0.1,0,0,100)
            end

            local BarRight2 = (Audio.PlaybackLoudness / 26)
            if BarRight2 <= 50 * 2 then
                Visual.BarRight2.Size = UDim2.new(0.1,0,0,BarRight2)
            else
                Visual.BarRight2.Size = UDim2.new(0.1,0,0,100)
            end
        end
    end)
--

This is inside a ServerScript, It's suppose to be keeping the SurfaceGui's in sync. What am I doing wrong?