Http - invalid authentication method

Hi all,

I have created a rule, like this:

var url = "";
      var output = actions.HTTP.sendHttpGetRequest(url);

When I copy the url to my browser, I will get the expected json output.
But when I execute the rule I get:

  "success" : false,
  "error" : {
    "code" : 8,
    "description" : "invalid authentication method"

The certificate is valid. Before I had a no certificate and there was another error.

So how can I use the same authentification method as my browser does?