Warning: mysqli::__construct(): (HY000/2002): No such file or directory in /var/www/localhost/htdocs/piwi/piwigo/include/dblayer/functions_mysqli.inc.php on line 67

Warning: my_error(): Couldn't fetch mysqli in /var/www/localhost/htdocs/piwi/piwigo/include/dblayer/functions_mysqli.inc.php on line 837

Warning: my_error(): Couldn't fetch mysqli in /var/www/localhost/htdocs/piwi/piwigo/include/dblayer/functions_mysqli.inc.php on line 837

Piwigo encountered a non recoverable error

[mysql error ] 
Can't connect to server

#1	my_error /var/www/localhost/htdocs/piwi/piwigo/include/common.inc.php(128)
#2	include_once /var/www/localhost/htdocs/piwi/piwigo/picture.php(25)