If you have provided the correct details of your database and still see the red cross icon, please ensure:
a) allow_url_fopen is enabled i.e. allow_url_foopen=on in your php.ini and restart your apache server
b) PDO driver such as MySQL is installed
c) Read-write permission for Dashboardbuilder folders and subfolders, i. e chmod -R 777 dashboard-builder-v38-FREE