diff --git a/application/controllers/Google.php b/application/controllers/Google.php
index 016f462a..455d8908 100644
--- a/application/controllers/Google.php
+++ b/application/controllers/Google.php
@@ -82,29 +82,37 @@ class Google extends CI_Controller {
      */
     public function oauth_callback()
     {
-        if ($this->input->get('code'))
+        $code = $this->input->get('code');
+
+        if (empty($code))
         {
-            $this->load->library('Google_sync');
-            $token = $this->google_sync->authenticate($this->input->get('code'));
+            $this->output->set_output('Code authorization failed.');
+            return;
+        }
 
-            // Store the token into the database for future reference.
-            $oauth_provider_id = $this->session->userdata('oauth_provider_id');
+        $this->load->library('Google_sync');
 
-            if ($oauth_provider_id)
-            {
-                $this->load->model('providers_model');
-                $this->providers_model->set_setting('google_sync', TRUE, $oauth_provider_id);
-                $this->providers_model->set_setting('google_token', $token, $oauth_provider_id);
-                $this->providers_model->set_setting('google_calendar', 'primary', $oauth_provider_id);
-            }
-            else
-            {
-                $this->output->set_output('<h1>Sync provider id not specified!</h1>');
-            }
+        $token = $this->google_sync->authenticate($code);
+
+        if (empty($token))
+        {
+            $this->output->set_output('Token authorization failed.');
+            return;
+        }
+
+        // Store the token into the database for future reference.
+        $oauth_provider_id = $this->session->userdata('oauth_provider_id');
+
+        if ($oauth_provider_id)
+        {
+            $this->load->model('providers_model');
+            $this->providers_model->set_setting('google_sync', TRUE, $oauth_provider_id);
+            $this->providers_model->set_setting('google_token', json_encode($token), $oauth_provider_id);
+            $this->providers_model->set_setting('google_calendar', 'primary', $oauth_provider_id);
         }
         else
         {
-            $this->output->set_output('<h1>Authorization Failed!</h1>');
+            $this->output->set_output('Sync provider id not specified.');
         }
     }
 
diff --git a/application/libraries/Google_sync.php b/application/libraries/Google_sync.php
index 07388b7d..00cfaa13 100644
--- a/application/libraries/Google_sync.php
+++ b/application/libraries/Google_sync.php
@@ -62,7 +62,11 @@ class Google_Sync {
         $this->client->setClientSecret($this->framework->config->item('google_client_secret'));
         $this->client->setDeveloperKey($this->framework->config->item('google_api_key'));
         $this->client->setRedirectUri(site_url('google/oauth_callback'));
-        $this->client->setScopes('https://www.googleapis.com/auth/calendar');
+        $this->client->setAccessType('offline');
+        $this->client->addScope([
+            Google_Service_Calendar::CALENDAR,
+            Google_Service_Calendar::CALENDAR_READONLY
+        ]);
 
         $this->service = new Google_Service_Calendar($this->client);
     }
@@ -88,12 +92,22 @@ class Google_Sync {
      * provided. Using this code, we can authenticate the API usage and store the
      * token information to the database.
      *
-     * @see Google Controller
+     * @param $code
+     *
+     * @return array
+     *
+     * @throws Exception
      */
-    public function authenticate($auth_code)
+    public function authenticate($code)
     {
-        $this->client->authenticate($auth_code);
-        return $this->client->getAccessToken();
+        $response = $this->client->fetchAccessTokenWithAuthCode($code);
+
+        if (isset($response['error']))
+        {
+            throw new Exception('Google Authentication Error (' . $response['error'] . '): ' . $response['error_description']);
+        }
+
+        return $response;
     }
 
     /**
diff --git a/assets/js/backend_calendar_default_view.js b/assets/js/backend_calendar_default_view.js
index 26d753ac..b4cfbe97 100755
--- a/assets/js/backend_calendar_default_view.js
+++ b/assets/js/backend_calendar_default_view.js
@@ -250,12 +250,12 @@ window.BackendCalendarDefaultView = window.BackendCalendarDefaultView || {};
 
                 // If the user has already the sync enabled then apply the proper style changes.
                 if ($('#select-filter-item option:selected').attr('google-sync') === 'true') {
-                    $('#enable-sync').addClass('btn-danger enabled');
-                    $('#enable-sync span:eq(1)').text(EALang.disable_sync);
+                    $('#enable-sync').removeClass('btn-light').addClass('btn-danger enabled');
+                    $('#enable-sync span').text(EALang.disable_sync);
                     $('#google-sync').prop('disabled', false);
                 } else {
-                    $('#enable-sync').removeClass('btn-danger enabled');
-                    $('#enable-sync span:eq(1)').text(EALang.enable_sync);
+                    $('#enable-sync').removeClass('btn-danger enabled').addClass('btn-light');
+                    $('#enable-sync span').text(EALang.enable_sync);
                     $('#google-sync').prop('disabled', true);
                 }
             }
diff --git a/assets/js/backend_calendar_google_sync.js b/assets/js/backend_calendar_google_sync.js
index 6f3a85c7..19268859 100644
--- a/assets/js/backend_calendar_google_sync.js
+++ b/assets/js/backend_calendar_google_sync.js
@@ -53,8 +53,8 @@ window.BackendCalendarGoogleSync = window.BackendCalendarGoogleSync || {};
                                 // The user has granted access to his data.
                                 windowHandle.close();
                                 window.clearInterval(authInterval);
-                                $('#enable-sync').addClass('btn-danger enabled');
-                                $('#enable-sync span:eq(1)').text(EALang.disable_sync);
+                                $('#enable-sync').addClass('btn-danger enabled').removeClass('btn-light');
+                                $('#enable-sync span').text(EALang.disable_sync);
                                 $('#google-sync').prop('disabled', false);
                                 $('#select-filter-item option:selected').attr('google-sync', 'true');
 
@@ -71,8 +71,9 @@ window.BackendCalendarGoogleSync = window.BackendCalendarGoogleSync || {};
                                 $.post(url, data)
                                     .done(function (response) {
                                         $('#google-calendar').empty();
-                                        response.forEach(response, function (event) {
-                                            $('#google-calendar').append(new Option(event.summary, event.id));
+
+                                        response.forEach(function (calendar) {
+                                            $('#google-calendar').append(new Option(calendar.summary, calendar.id));
                                         });
 
                                         $('#select-google-calendar').modal('show');
@@ -94,7 +95,7 @@ window.BackendCalendarGoogleSync = window.BackendCalendarGoogleSync || {};
                 var providerId = $('#select-filter-item').val();
 
                 var provider = GlobalVariables.availableProviders.find(function (availableProvider) {
-                    return Number(provider.id) === Number(providerId);
+                    return Number(availableProvider.id) === Number(providerId);
                 });
 
                 provider.settings.google_sync = '0';
@@ -102,8 +103,8 @@ window.BackendCalendarGoogleSync = window.BackendCalendarGoogleSync || {};
 
                 disableProviderSync(provider.id);
 
-                $('#enable-sync').removeClass('btn-danger enabled');
-                $('#enable-sync span:eq(1)').text(EALang.enable_sync);
+                $('#enable-sync').removeClass('btn-danger enabled').addClass('btn-light');
+                $('#enable-sync span').text(EALang.enable_sync);
                 $('#google-sync').prop('disabled', true);
                 $('#select-filter-item option:selected').attr('google-sync', 'false');
             }