Hello,
If you are installing it on your website the DB server name is 'localhost' it self. If you are attempting to connect from your local machine use the server IP or your domain name as the DB server name .
If you are still facing issue , please open a ticket.
Hello,
It will be resolved faster if you include the following details,
You domain name, your phone number / zip code and the last 3 digits of your credit card, used to pay for the hosting, as a security check.