Warning: mysqli::mysqli(): (HY000/2002): No such file or directory in /share/CACHEDEV1_DATA/Web/piwigo/include/dblayer/functions_mysqli.inc.php on line 52

Warning: my_error(): Couldn't fetch mysqli in /share/CACHEDEV1_DATA/Web/piwigo/include/dblayer/functions_mysqli.inc.php on line 856

Warning: my_error(): Couldn't fetch mysqli in /share/CACHEDEV1_DATA/Web/piwigo/include/dblayer/functions_mysqli.inc.php on line 856

Piwigo encountered a non recoverable error

[mysql error ] 
Can't connect to server

#1	my_error /share/CACHEDEV1_DATA/Web/piwigo/include/common.inc.php(113)
#2	include_once /share/CACHEDEV1_DATA/Web/piwigo/plugins/download_by_size/action.php(32)