error

00:10:41.238 [error] Error in process <0.692.0> with exit value: {[{reason,undef},{mfa,{'Elixir.Site.Index',init,3}},{stacktrace,[{'Elixir.Site.Index',init,[{tcp,http},{http_req,#Port<0.6711>,ranch_tcp,keepalive,<0.692.0>,<<3 bytes>>,'HTTP/1.1',{{127,0,0,1},47170},<<9 bytes>>,undefined,8080,<<1 byte>>,undefined,<<0 bytes>>,undefined,[],[{<<4 bytes>>,<<14 bytes>>},{<<10 bytes>>,<<76 bytes>>},{<<6 bytes>>,<<63 bytes>>},{<<15 bytes>>,<<14 bytes>>},{<<15 bytes>>,<<13 bytes>>},{<<10 bytes>>,<<10 bytes>>},{<<13 bytes>>,<<9 bytes>>}],... 



00:10:41.272 [error] Ranch listener :my_http_listener had connection process started with :cowboy_protocol:start_link/4 at #PID<0.692.0> exit with reason: {[reason: :undef, mfa: {Site.Index, :init, 3}, stacktrace: [{Site.Index, :init, [{:tcp, :http}, {:http_req, #Port<0.6711>, :ranch_tcp, :keepalive, #PID<0.692.0>, "GET", :"HTTP/1.1", {{127, 0, 0, 1}, 47170}, "localhost", :undefined, 8080, "/", :undefined, "", :undefined, [], [{"host", "localhost:8080"}, {"user-agent", "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0"}, {"accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"}, {"accept-language", "en-US,en;q=0.5"}, {"accept-encoding", "gzip, deflate"}, {"connection", "keep-alive"}, {"cache-control", "max-age=0"}], [{"connection", ["keep-alive"]}], :undefined, [], :waiting, "", :undefined, false, :waiting, [], "", :undefined}, []], []}, {:cowboy_handler, :handler_init, 4, [file: 'src/cowboy_handler.erl', line: 64]}, {:cowboy_protocol, :execute, 4, [file: 'src/cowboy_protocol.erl', line: 442]}], req: [socket: #Port<0.6711>, transport: :ranch_tcp, connection: :keepalive, pid: #PID<0.692.0>, method: "GET", version: :"HTTP/1.1", peer: {{127, 0, 0, 1}, 47170}, host: "localhost", host_info: :undefined, port: 8080, path: "/", path_info: :undefined, qs: "", qs_vals: :undefined, bindings: [], headers: [{"host", "localhost:8080"}, {"user-agent", "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0"}, {"accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"}, {"accept-language", "en-US,en;q=0.5"}, {"accept-encoding", "gzip, deflate"}, {"connection", "keep-alive"}, {"cache-control", "max-age=0"}], p_headers: [{"connection", ["keep-alive"]}], cookies: :undefined, meta: [], body_state: :waiting, buffer: "", multipart: :undefined, resp_compress: false, resp_state: :waiting, resp_headers: [], resp_body: "", onresponse: :undefined], opts: []], [{:cowboy_protocol, :execute, 4, [file: 'src/cowboy_protocol.erl', line: 442]}]}