Unable to Authenticate user to HP ALM in Node.js using REST API

I am running a simple node.js code to authenticate the user to ALM 11.00. It was working 2 days back and now it fails to return the session-token

var https = require('https');
var http = require('http');
var user_ = 'userName';
var password_ = 'password';

var options = {
    host : "serverurl",
    path : "/qcbin/authentication-point/authenticate",
    method: "GET",
    headers : {'Content-Type': 'application/XML','Authorization': 'Basic '+new Buffer(user_ + ':' + password_).toString('base64')}
    };
    var req = http.request(options, function(res){
                    console.log('xyz '+ res.headers["set-cookie"]);
        res.setEncoding('utf8');
        var output='';
        res.on('data',function(chunk){
            output+=chunk;
        });
        res.on('end',function(){
            console.log('the message is '+ output);
        });
    });
    req.on('error',function(e){
        console.log('the erro msg'+ e);
    });
    req.end();

I am getting a Failed to log in. Login via SSL is required. error. But if I use the https to get the results then I end up gettng UNABLE_TO_VERIFY_LEAF_SIGNATURE error.

Still not sure why it was working fine 2 days back and now its just failing since nothing has changed on the ALM server