How do I make my script close a team switch GUI once the player has chose the team?

I am trying to make a switch team script and I am at the last part where I have to get the script to go invisible but it seems wherever I put the last part of code it doesn't work.

Script:

game.StarterGui.TeamSwitchGui.MainFrame.Visible = true
local TC = Instance.new("RemoteEvent")
TC.Name = "TeamChanger"
TC.Parent = game.ReplicatedStorage

TC.OnServerEvent:Connect(function(Player, TeamName)
    Player.Team = game.Teams[TeamName]
    game.StarterGui.TeamSwitchGui.MainFrame.Visible = false -----Part that is not working
    Player:LoadCharacter()
end)

Please help.