Piwigo encountered a non recoverable error

[mysql error 2003] Can't connect to MySQL server on 'atanasov.be' (111)
Can't connect to server

#1	my_error /home/www/atanasov.be/ivan/include/common.inc.php(120)
#2	include_once /home/www/atanasov.be/ivan/index.php(26)