Warning: mysql_pconnect(): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2) in /var/www/vhosts/motel.co.nz/httpdocs/lib/Connection.php on line 79

Fatal error: Uncaught exception 'NoConnectionException' with message 'Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)' in /var/www/vhosts/motel.co.nz/httpdocs/lib/Connection.php:83
Stack trace:
#0 /var/www/vhosts/motel.co.nz/httpdocs/lib/Connection.php(68): Connection::init()
#1 /var/www/vhosts/motel.co.nz/httpdocs/lib/Connection.php(144): Connection::log('unlock tables;')
#2 /var/www/vhosts/motel.co.nz/httpdocs/index.php(9): Connection::update('unlock tables;')
#3 {main}
  thrown in /var/www/vhosts/motel.co.nz/httpdocs/lib/Connection.php on line 83