diff --git a/src/Util/Exception/AuthenticationException.php b/src/Util/Exception/AuthenticationException.php
new file mode 100644
index 0000000000..7fa36c2525
--- /dev/null
+++ b/src/Util/Exception/AuthenticationException.php
@@ -0,0 +1,39 @@
+<?php
+
+// {{{ License
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// GNU social 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.
+// }}}
+
+/**
+ * Error when authenticating
+ *
+ * @category  Exception
+ * @package   GNUsocial
+ *
+ * @author    Hugo Sales <hugo@hsal.es>
+ * @copyright 2021 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+
+namespace App\Util\Exception;
+
+class AuthenticationException extends ClientException
+{
+    public function __construct(string $msg)
+    {
+        parent::__construct($msg, 401); // 401 Unauthorized
+    }
+}