DreamFactory on Centos Plesk with Virtual Host

I have tried the same on CentOS 7 system. Mine is fresh DFS installation. I have followed the official documentation. When I try to launch the web console in browser, it shows the error “CDbConnection failed to open the DB connection”. What could be the problem? I disabled SELinux too. I have set all permissions as shown in the official wiki document. Pls help.