Cannot fire an event with a part touch, what is wrong ?

Hello Gingerely

Thanks for the question

Basically, because I guess you're using a server script, inside of a part, you can just do everything here, as the serverscript is safe, and the client can not edit this, meaining you will not need to fire the server.

RemoteEvents, allow the server and the Client to interact / communicate.

Since you're already using a serverscript, you can do this

local debounce = false

script.Parent.Touched:Connect(function(hit)
    if debounce == false then -- checking for debounce
        debounce = true -- because player has touched.
        if hit.Parent:FindFirstChild("Humanoid") then -- has found a player.
            local player = game:GetService("Players"):GetPlayerFromCharacter(hit.Parent) -- gets the player inside of the 'Players' service.
            --Add the players currency here example;
            player.leaderstats["Currency2"].Value = player.leaderstats["Currency1"].Value * 2 --EXAMPLE.
            player["Currency1"].Value = 0 --EXAMPLE.
            wait(2)
            debounce = false
        end
    end
end)

This must be server script then, change it to a Local Script!