How do I fix the script when it thinks the TextBox says nothing?

Here's the script:

local Frame = script.Parent.Parent
local CodeBox = Frame.UserCodeBox
local Code = script.Code
local Instruction = Frame.Instructions
local Player = script.Player

script.Parent.MouseButton1Click:Connect(function(click)
	if Instruction.Text == "Please input your Username now to continue." then
		local Plr = game.Players:FindFirstChild(CodeBox.Text)
		if Plr ~= nil then
			Player.Value = CodeBox.Text
			CodeBox.Text = ""
			Instruction.Text = "Username accepted. Please input your new Password now to continue."
		else
			CodeBox.Text = ""
			Instruction.Text = "Username "..CodeBox.Text.." has been rejected. Please retry."
			wait(2)
			Instruction.Text = "Please input your Username now to continue."
		end
	elseif Instruction.Text == "Username accepted. Please input your new Password now to continue." then
		if CodeBox.Text == "" then
			Instruction.Text = "Your password needs to have at least one character."
			wait(2)
			Instruction.Text = "Username accepted. Please input your new Password now to continue."
		else
			Code.Value = CodeBox.Text
			Instruction.Text = "Password accepted. Please input your password again to verify and finish."		
		end
	elseif Instruction.Text == "Password accepted. Please input your password again to verify and finish." then
		if CodeBox.Text == Code.Value then
			game.ReplicatedStorage.PlayerStats[Player.Value].UserCode.Value = CodeBox.Text
			Instruction.Text = "New password set! Returning to Login page now!"
			wait(2)
			Instruction.Text = "Please input your Username now to continue."
			Frame.Parent.Login.Visible = true
			Frame.Visible = false
		else
			Instruction.Text = "Codes do not match. Please retry."
			wait(2)
			Instruction.Text = "Password accepted. Please input your password again to verify and finish."
		end
    end
end)

It's a Complex Script, but I need help with my new PC Software. Little help. Thanks!

Btw, the error is from line 8 to 19