Fatal error: Uncaught mysqli_sql_exception: MySQL server has gone away in /var/www/html/mybb/inc/db_mysqli.php:337
Stack trace:
#0 /var/www/html/mybb/inc/db_mysqli.php(337): mysqli_query()
#1 /var/www/html/mybb/inc/db_mysqli.php(798): DB_MySQLi->query()
#2 /var/www/html/mybb/showthread.php(454): DB_MySQLi->simple_select()
#3 {main}
thrown in /var/www/html/mybb/inc/db_mysqli.php on line 337