Connect to localhost:journal_jnsee failed:

Fatal error: Uncaught Exception: MySQL server has gone away in /opt/lampp/htdocs/jnsee/includes/awtdbfile-p7.php:2 Stack trace: #0 /opt/lampp/htdocs/jnsee/includes/awtdbfile-p7.php(2): db->__construct() #1 /opt/lampp/htdocs/jnsee/includes/awtdbfile-p7.php(2): db::getInstance() #2 /opt/lampp/htdocs/jnsee/common.php(2): include_once('/opt/lampp/htdo...') #3 /opt/lampp/htdocs/jnsee/form_register.php(1): require_once('/opt/lampp/htdo...') #4 {main} thrown in /opt/lampp/htdocs/jnsee/includes/awtdbfile-p7.php on line 2