Billboard gui not showing up and color changer isn't working?

local char = player.Character
			local head = char:FindFirstChild("Head")
			local bgui = Instance.new("BillboardGui")
			bgui.Parent = head
			bgui.Size = UDim2.new(1,0,1,0)
			bgui.Adornee = head
			bgui.StudsOffset = Vector3.new(0,2,0)
			bgui.AlwaysOnTop = true
			local frame = Instance.new("Frame")
			frame.Parent = bgui
			frame.BackgroundTransparency = 0.4
			if player.Team == "Yellow" then -- Yellow is the team name not team color
				frame.BackgroundColor3 = BrickColor.new("Buttermilk").Color
			elseif player.Team == "Green" then -- Green is team name not team color
				frame.BackgroundColor3 = BrickColor.new("Mint").Color
			end 

The billboard gui is in the player's head, but not showing up. Also, the "BackgroundColor3" property doesn't change. There's no error in the output, and this is only a portion of the script. Could somebody help?

local char = player.Character
            local head = char:FindFirstChild("Head")
            local bgui = Instance.new("BillboardGui")
            bgui.Parent = head
            bgui.Size = UDim2.new(1,0,1,0)
            bgui.Adornee = head
            bgui.StudsOffset = Vector3.new(0,2,0)
            bgui.AlwaysOnTop = true
            local frame = Instance.new("Frame")
            frame.Parent = bgui
            frame.BackgroundTransparency = 0.4
            if player.Team == game.Teams:FindFirstChild("Yellow") then -- Yellow is the team name not team color
                frame.BackgroundColor3 = BrickColor.new("Buttermilk").Color
            elseif player.Team == game.Teams:FindFirstChild("Green") then -- Green is team name not team color
                frame.BackgroundColor3 = BrickColor.new("Mint").Color
            end

player.Team is always linked to an actual team, not a name.