httprc:request throws exception exit: {noproc, {gen_server,call, [httpc_manager ...]}}

I want to invoke httprc:request in my erlang program, but I get an exception, which has no information to me, what went wrong.

This is my code:

print_helloworld() ->
  Body = "userId=12345",
  httpc:request(post,
    {
    "'http://192.168.2.100:8080/010/xmppcontrol", [],
      "application/x-www-form-urlencoded",
      Body
    }, [], []).

This is my exception:

1> hello_world:print_helloworld().
** exception exit: {noproc,
                    {gen_server,call,
                     [httpc_manager,
                      {request,
                       {request,undefined,<0.58.0>,0,'\'http',
                        {"192.168.2.100",8080},
                        "/010/xmppcontrol",[],post,
                        {http_request_h,undefined,"keep-alive",undefined,
                         undefined,undefined,undefined,undefined,undefined,
                         undefined,...},
                        {"application/x-www-form-urlencoded","userId=12345"},
                        {http_options,"HTTP/1.1",infinity,true,
                         {essl,[]},
                         undefined,false,infinity,...},
                        "'http://192.168.2.100:8080/010/xmppcontrol",[],none,
                        [],1510504662776,undefined,undefined,false}},
                      infinity]}}
     in function  gen_server:call/3 (gen_server.erl, line 214)
     in call from httpc:handle_request/9 (httpc.erl, line 554)

Can you tell what is wrong in the httpc:request call, because when I call the URL from JS, it works fine.

This is my code from JavaScript:

var XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;
asyncRequest = new XMLHttpRequest();
asyncRequest.addEventListener("readystatechange", stateChange, false);
asyncRequest.open('POST', 'http://192.168.2.100:8080/010/xmppcontrol?userId=' + userId , true);
asyncRequest.send(null);

Thanks in advance.

The error message says that there's no process running that is bound to the name httpc_manager. As documented in httpc and inets, you need to have the inets application running to make httpc requests work. You can do this either by adding the application to the applications list when using rebar (in src/....app.src) or starting the inets application manually, e.g.

inets:start(),
httpc:request(...).