Please note: These are general points, which apply to *any* application that uses a MySQL database. They are not particular to simpleContact.
------------------------------------------
MySQL database connection
In the majority of cases, your MySQL database server is accessible through the default setting of "localhost". However some hosts choose to store their databases elsewhere.
On GoDaddy your database host is unique to your account. You must log in to your control panel and navigate to your MySQL settings to find out what it should be:
1) Log in to your Account Manager
2) In the My Products section, select Hosting
3) Next to the hosting account you want to modify, click Manage Account
4) In the Databases section of the Hosting Control Center, click the MySQL icon
5) From your list of databases, click the Pencil icon next to the database you want information about
6) The Database Information page displays. You will find the host name for your database on this page
You should set the $server (Lite) or $db_host (Pro) setting in your config file to reflect this.
Reference: What do I use for a host name when creating a MySQL database? (GoDaddy Knowledge Base)