diff --git a/blocks/tag_youtube/edit_form.php b/blocks/tag_youtube/edit_form.php
index 75e5c0dc623..16a83077435 100644
--- a/blocks/tag_youtube/edit_form.php
+++ b/blocks/tag_youtube/edit_form.php
@@ -42,19 +42,21 @@ class block_tag_youtube_edit_form extends block_edit_form {
 
         // Category setting.
         $categorychoices = ['0' => get_string('anycategory', 'block_tag_youtube')];
+        $hascategoryerror = false;
         $categoryerror = '';
 
         try {
             // Get all video categories through an API call and add them to the category list.
             $categorychoices += $this->block->get_categories();
         } catch (Exception $e) {
+            $hascategoryerror = true;
             $categoryerror = $e->getMessage();
         }
         $mform->addElement('select', 'config_category', get_string('category', 'block_tag_youtube'),
             $categorychoices);
         $mform->setDefault('config_category', 0);
 
-        if ($categoryerror) {
+        if ($hascategoryerror) {
             $notification = $OUTPUT->notification(get_string('categoryerror', 'block_tag_youtube', $categoryerror),
                 'error');
             $mform->addElement('static', 'config_category_error', '', $notification);
diff --git a/lib/google/curlio.php b/lib/google/curlio.php
index 72e7d2fb859..ed2ceb54e6d 100644
--- a/lib/google/curlio.php
+++ b/lib/google/curlio.php
@@ -124,7 +124,7 @@ class moodle_google_curlio extends Google_IO_Curl {
         $curlerrornum = $curl->get_errno();
         $curlerror = $curl->error;
 
-        if ($respdata != CURLE_OK) {
+        if ($curlerrornum != CURLE_OK) {
             throw new Google_IO_Exception($curlerror);
         }
 
diff --git a/lib/tests/googlelib_test.php b/lib/tests/googlelib_test.php
new file mode 100644
index 00000000000..6a3a9fb24d8
--- /dev/null
+++ b/lib/tests/googlelib_test.php
@@ -0,0 +1,40 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Tests for google library
+ *
+ * @package    core
+ * @copyright  2021 Marina Glancy
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class core_googlelib_testcase extends advanced_testcase {
+
+    public function test_invalid_google_api_key() {
+        global $CFG;
+        require_once($CFG->libdir . '/google/lib.php');
+        $client = get_google_client();
+        $client->setDeveloperKey('invalid');
+        $client->setScopes(array(Google_Service_YouTube::YOUTUBE_READONLY));
+        $service = new Google_Service_YouTube($client);
+        try {
+            $service->videoCategories->listVideoCategories('snippet', ['regionCode' => 'us']);
+            $this->fail('Exception expected');
+        } catch (Google_Service_Exception $e) {
+            $this->assertEquals(1, preg_match('/API key not valid/', $e->getMessage()));
+        }
+    }
+}