Automatically authenticate a user in Moodle

I am trying to automatically authenticate a user in Moodle but having trouble using authenticate_user_login in Moodle 3.8.3. I have tested the below code but I get the following error: Exception - Argument 1 passed to core\session\manager::login_user() must be an instance of stdClass, boolean given, called in [dirroot]/lib/moodlelib.php on line 4632 Appreciate your help. ``` <?php require('config.php'); $name="myusername"; $password="mypassword"; $dashboard = $CFG->wwwroot; $user = authenticate_user_login($name, $password); if(complete_user_login($user)) { echo "login"; } else { echo "not login"; } ?> ```