SharePoint (and Project Server) Shenanigans

The issue occurred while running SharePoint 2010 setup, after installing pre-requisites, and following first few initial screens of setup wizard. Once reached to the point where you can enter SharePoint database server name, and credentials which can be used to talk to database server. You may see this error:

Cannot connect to database master at SQL Server at <server_name>. The database might not exist, or the current user does not have permission to connect to it.

Now if you have followed the recommended technet article to setup service accounts and permission, this error might be little misleading at the start. But root cause of the issue is completely valid.

There is already a very detailed and helpful blog is available for you to follow to start troubleshooting:
http://blogs.technet.com/b/tothesharepoint/archive/2011/01/12/troubleshooting-sharepoint-configuration-error-cannot-connect-to-database-master-at-server-name.aspx

The possible causes of that error are as follows, first 2 are available in this blog, and the 3rd is the one i found and is the reason of this post:

1. Permissions of the account used to configure has correct permission within SQL based on technet article.
2. SQL Server in windows firewall required port, by default its 1433, is allowed to receive traffic from SharePoint application server.
3. Verify that user through which you are running setup has got permissions to login to SQL Server. Yes, its very common in production or customer environments that you use different credentials to login to server than to the one you use to for deployment. Now either allow that user login permission to SQL Server by going to SQL Server and adding that user under logins within security of SQL Server. Or, run the setup as an administrator. In fact a good practice, is to always run the setup as an administrator to avoid such glitches.

Have a good day at work.