Why did I get HTTP 0 (HTTP 400 (HTTP/1.1 400 UserOffline))?

I'm using GetPlayerPlaceInstanceAsync in a game. Its a lobby with five other places in that whole game. Trying to script player following (heh)

Whenever I call GetPlayerPlaceInstanceAsync on a player's userId who is in one of the five places, I get this strange error. The user is not offline, in fact he/she is playing in that game.

This is a FilteringEnabled game. Assuming that "playerData" as a table {username, userid}

GLOBAL

function game.ReplicatedStorage.TeleportFinder.OnServerInvoke(player, text)
	local playerData = playerList:GetAsync(text)
	if playerData == nil then
		return {false}
	else
		print(playerData[1], playerData[2])
		if playerData[2] == true then
			local sus, er, placeid, instid = game:GetService('TeleportService'):GetPlayerPlaceInstanceAsync(playerData[2])
			return {true, playerData[1], sus, er, placeid, instid}
		else
			return {false}
		end
	end
end

LOCAL (JoinFriend is a "TextBox", and PlayerCheckDebounce is a variable)

Frame.Games.JoinFriend.FocusLost:connect(function(EnterPressed)
	if not PlayerCheckDebounce then
		local tab = game.ReplicatedStorage.TeleportFinder:InvokeServer(string.lower(Frame.Games.JoinFriend.Text))
		-- ... and it goes on
	end
end

I would appreciate it if someone helped :)

• Iiau