This operation can be performed only on a computer that is joined to a server farm by users who have permissions in SQL Server to read from the configuration database. To connect this server to the server farm, use the SharePoint Products Configuration Wizard, located on the Start menu in Microsoft SharePoint 2010 Products.

When I was tried to access SharePoint 2013 application, I got below error. It gave me the same error while accessing the Central Administration too.

This error occurs due to SQL Server service is not started.

To start the service Go to Start >> Run >> Services.msc >> SQL Server (MSSQLServer)
Click on Start

Navigate to the browser and refresh the page, SharePoint 2013 web application is working fine.

Enjoy SharePoint!!!