Warning: require_once(/var/www/html/wp-content/plugins/onecode-login/includes/class-email-sender.php): Failed to open stream: Permission denied in /var/www/html/wp-content/plugins/onecode-login/onecode-login.php on line 78

Fatal error: Uncaught Error: Failed opening required '/var/www/html/wp-content/plugins/onecode-login/includes/class-email-sender.php' (include_path='.:/usr/local/lib/php') in /var/www/html/wp-content/plugins/onecode-login/onecode-login.php:78
Stack trace:
#0 /var/www/html/wp-content/plugins/onecode-login/onecode-login.php(65): OneCode_Login->load_dependencies()
#1 /var/www/html/wp-content/plugins/onecode-login/onecode-login.php(53): OneCode_Login->__construct()
#2 /var/www/html/wp-content/plugins/onecode-login/onecode-login.php(318): OneCode_Login::get_instance()
#3 /var/www/html/wp-settings.php(560): include_once('/var/www/html/w...')
#4 /var/www/html/wp-config.php(142): require_once('/var/www/html/w...')
#5 /var/www/html/wp-load.php(50): require_once('/var/www/html/w...')
#6 /var/www/html/wp-blog-header.php(13): require_once('/var/www/html/w...')
#7 /var/www/html/index.php(17): require('/var/www/html/w...')
#8 {main}
  thrown in /var/www/html/wp-content/plugins/onecode-login/onecode-login.php on line 78