Warning: mysqli_real_connect(): MySQL server has gone away in /var/www/nexusddl.com/htdocs_new/src/DB.php on line 49

Warning: mysqli_real_connect(): Error while reading greeting packet. PID=15363 in /var/www/nexusddl.com/htdocs_new/src/DB.php on line 49

Warning: mysqli_real_connect(): (HY000/2006): MySQL server has gone away in /var/www/nexusddl.com/htdocs_new/src/DB.php on line 49

Fatal error: Uncaught exception 'DB\Exception\ConnectionException' with message 'Couldnt connect to "mysqli://root@db:3306/nexusddl_v3"' in /var/www/nexusddl.com/htdocs_new/src/DB.php:55
Stack trace:
#0 /var/www/nexusddl.com/htdocs_new/include/common.php(15): DB::Connect('db', 'root', 'passwordmysql', 'nexusddl_v3')
#1 /var/www/nexusddl.com/htdocs_new/handle.php(50): include('/var/www/nexusd...')
#2 {main}
  thrown in /var/www/nexusddl.com/htdocs_new/src/DB.php on line 55