SharePoint Farm Configuration Error

I'm trying to install SharePoint Server 2013 Enterprise Edition SP 1. When I run the Configuration Wizard, select "Create a new server farm", and then enter the details for my Database server, it throws the following error:

The username is invalid. The account must be a valid domain account.

I've also tried running New-SPConfigurationDatabase command from SharePoint 2013 Management Shell. (Yes, I tried running it as administrator as well.) I get the following error:

New-SPConfigurationDatabase : DOMAIN\USERNAME At line:1 char: 1 + New-SPConfigurationDatabase + ~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : InvalidData: <Microsoft.Share...urationDatabase: SPCmdletNewSPConfigurationDatabase> [New-SPConfigurationDatabase], Win32EXception + FullyQualifiedErrorId : Microsoft.SharePoint.PowerShell.SPCmdletNewSPConfigurationDatabase

I've checked the Database Server, it uses Windows Authentication for the SQL Server, and uses the same user account I'm providing to SharePoint Configuration Wizard.

Do you have any idea why this might be happening?

Thanks in advance.