Changing Teams with gamepasses?

Hello everyone,

I've recently began working on my own game which has resulted in multiple errors. I'm used to working with C# and since Roblox used Lua. Well yea... I've looked through multiple forums, tutorials and a little bit on this website for a solution to my problem. I'm trying to make a player change teams when pressing a button on a gui whilst checking the gamepass. As gamepassservice requires the script to be server sided I can't use a localscript. In the Roblox studio this code works but when I go in-game and I press the gui it doesn't.

This is my script:

local gamepassID = ******

script.Parent.MouseButton1Click:connect(function (playerWhoClicked)
    local player = game.Players.LocalPlayer
    local gps = game:GetService("GamePassService")
    local playerHasPass = gps:PlayerHasPass(player, gamepassID)

    if playerHasPass then
        player.Team = game.Teams.HATO
    else
        gps:PromptPurchase(player, gamepassID)
    end
end)

Kind regards,

SamDeNormaleAap