Trello Script not working, Argument 2 Missing or Nil?

So I have a trello script that I'm working on for a game, the getasync works fine, but when I try to post a card to a list, it doesn't work.

http = game:GetService("HttpService")
lists = "https://api.trello.com/1/lists/"
idagentreports = "5a406f099038ed77a724c89a"
auth = "&key="..tkey.."&token="..ttoken..""
local namefield = script.Parent.bg.agentreportnamebox.Text
local prooffield = script.Parent.bg.agentreportproofbox.Text

Above are my variables, tkey is my trello key and ttoken is my trello token.

script.Parent.bg.agentreportsubmitbtn.MouseButton1Click:connect(function()
		print("clicked")
		local postcard = http:PostAsync("https://api.trello.com/1/cards?name="..namefield.."&desc="..prooffield.."&pos=top&idList="..idagentreports..""..auth.."")
		print("submitted")
end)

Above is what I'm trying to submit, but it's not working. I tried adding http:JSONEncode, but that didn't work either.

The output says Argument 2 missing or nil.