Database connection failed!

Stack Trace:

File: /srv/u01/www/anais.uel.br/ojs-3.1.1-4/classes/core/Application.inc.php line 38
Function: PKPApplication->__construct()

File: /srv/u01/www/anais.uel.br/ojs-3.1.1-4/lib/pkp/includes/bootstrap.inc.php line 58
Function: Application->__construct()

File: /srv/u01/www/anais.uel.br/ojs-3.1.1-4/index.php line 73
Function: require("/srv/u01/www/anais.uel.br/ojs-3.1.1-4/lib/pkp/includes/bootstrap...")