I made this ban GUI and it's not working! Can someone please help me?

So, I made this ban GUI script but when I run it, it says in the output that the player does not exist.

Here's the local script in the GUI.

local Username = script.Parent.Parent.Username.TextBox.Text
local Reason = script.Parent.Parent.Reason.TextBox.Text
local Evidence = script.Parent.Parent.Evidence.TextBox.Text

script.Parent.MouseButton1Click:Connect(function()
	print("Button was pressed!")
	if game.Players:FindFirstChild(Username) then
		print("Succesfully got a player!")
		game.ReplicatedStorage.ModEvents.BanPlayer:FireServer(Username, Reason)
	else
		print("Player does not exist!")
	end
end)

Here's the output when I press it:

https://prnt.sc/trdnbd

And here's the server script that gets the remote event:

game.ReplicatedStorage.ModEvents.BanPlayer.OnServerEvent:Connect(function(player, Username, Reason)
	game.Players:FindFirstChild(Username):Kick("\nYou have been banned for:\n"..Reason.."\n By: "..player.Name.. " | "..player.UserId)
	game.Players:FindFirstChild(Username).modstats.Banned.Value = true
	if game.Players:FindFirstChild(Username).modstats.Banned.Value == true then
		game.Players:FindFirstChild(Username):Kick("\nYou are for:\n"..Reason.."\n By: "..player.Name.. " | "..player.UserId)
	end
end)

Can someone help?