Log in function goes into error (on android device only)

Hi,

I’m having an issue logging in to my app on an android device.
This is the code I’m using:

var login = function(user, callback) {
    show_spinner();
    $http({
            url: BACKEND_URL.baseURL+BACKEND_URL.loginURL,
            method: "POST",
            headers: {"Content-Type": "application/x-www-form-urlencoded"},
            data: $.param({email:user.username, password:user.password})
    }).success(function(data, status, headers, config) {
                hide_spinner();
                var responseData = JSON.parse(JSON.stringify(data));
                if(responseData.isValid == "invalid")
                {
                    //alert("Username and password are not valid. Please try again.");
                    $ionicPopup.alert({
                        title: 'Failure',
                        template: 'Username and password are not valid. Please try again.'
                    });
                }
                else{
                    var userData = responseData.user;
                    console.log(userData);
                    user_id = userData.id;
                    user_email = userData.email;
                    storeUserCredentials(user.username, user.password);
                    callback("success");
                }
    }).error(function(data, status, headers, config) {
            callback("failure");
            hide_spinner();
            $ionicPopup.alert({
                title: 'Error',
                template: data
            });                      
    });
  };

If I test the app in my browser (ionic serve), it all works well.
If I test it on iPhone, it works well too.
Except on an android emulator or device, it won’t log in.
If I test it with the ionic view app, it does work (on every device)
Does anybody have any tips what to do?
I run the command: cordova run android, it install and runs on my device, but when i want to log in, it calls the error function from above immediately:

error(function(data, status, headers, config) {
            callback("failure");
            hide_spinner();
            $ionicPopup.alert({
                title: 'Error',
                template: data
            });    

Also, I started searching and ended on the ‘whitelist’ plugin, I already added this to my config.xml file

<access origin="*"/>
<allow-intent href="*.ionic.io"/>
<allow-intent href="*"/>
<allow-navigation href="*" />

Just to test to see if it would make any difference, but it didn’t.

Thank you!

Give us some info about the error params that the error handler function gets.