My lobby looks fine, but when I try to press the host button, Godot gives me this:

E 0:00:06.634 Object::emit_signal: Error calling method from signal 'lobby_joined': 'Control(Online.gd)::_on_Lobby_Joined': Method not found..
<C++ Source> core\object.cpp:1236 @ Object::emit_signal()
<Stack Trace> SteamGlobal.gd:27 @ _process()

The lobby code looks like this:

func _ready():
	steamName.text = SteamGlobal.STEAM_NAME
	
	Steam.connect("lobby_created", self, "_on_Lobby_Created")
	Steam.connect("lobby_match_list", self, "_on_Lobby_Match_List")
	Steam.connect("lobby_joined", self, "_on_Lobby_Joined")
	Steam.connect("lobby_chat_update", self, "_on_Lobby_Chat_Update")
	Steam.connect("lobby_message", self, "_on_Lobby_Data_Update")
	Steam.connect("join_requested", self, "_on_Lobby_Join_Requested")
	check_command_line()

func create_lobby():
	if SteamGlobal.LOBBY_ID == 0:
		Steam.createLobby(lobby_status.Public, 4)

func display_Message(message):
	lobbyOutput.add_text("\n" + str(message))

func _on_Lobby_Created(connect, lobbyID):
	if connect == 1:
		SteamGlobal.LOBBY_ID = lobbyID
		display_Message("Created Lobby: " + lobbySetName.text)
		
		Steam.setLobbyData(lobbyID, "name", lobbySetName.text)
		var name = Steam.getLobbyData(lobbyID, "name")
		lobbyGetName.text = str(name)

What am I doing wrong? I literally see no spelling errors...

Tutorial I'm following:

It's telling you it can't find any method called _on_Lobby_Joined. For that matter I don't see any of the others either except for _on_Lobby_Created in your code excerpt, they all need to defined (or inherited) in your script for those connect calls to work.