Error valid member of player?

I am scripting a room giver I have done all the coding that I can possibly do but it says Enter username is not a valid member of Players when I enter their name in the room giver. Heres what I have if you have anything that can help please let me know.

script.Parent.confirm.MouseButton1Click:connect(function()
    if script.Parent.errormsg.Text == "Error: Room not available" then
        warn("Room not available") else
        if game.Players[script.Parent.username.Text] then
        game.ServerStorage.ReceptionSystem.RoomsFolder["Room"..script.Parent.roomnum.Text].Value = true
        local newVal = Instance.new("StringValue", game.ServerStorage.ReceptionSystem.CheckedIn)
        newVal.Name = "Room"..script.Parent.roomnum.Text
        newVal.Value = game.Players[script.Parent.username.Text].Name
        local newKey = game.ServerStorage.ReceptionSystem.Card:Clone()
        newKey.Parent = game.Players[script.Parent.username.Text].Backpack
        newKey.Name = "Room "..script.Parent.roomnum.Text
        newKey.CardNumber.Value = script.Parent.roomnum.Text
        script.Parent.confirm.Text = "Checked in!"
        script.Parent.roomnum.Text = "Enter room number"
        script.Parent.username.Text = "Enter username"
        wait(0.5)
        script.Parent.confirm.Text = "Check-in"
        end
    end 
end)

script.Parent.roomnum.Changed:connect(function()
    script.Parent.errormsg.Text = " "
    if game.ServerStorage.ReceptionSystem.CheckedIn["Room"..script.Parent.roomnum.Text] then
        script.Parent.errormsg.Text = "Error: Room not available"
    end
end)

I always get error around line 4

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