Timeout Error from Excel Services - "Unable to refresh data for a data connection in the workbook"

Applies to: SharePoint 2010 Excel Services, SQL Server 2005, 2008, 2008 R2, 2012 Analysis Services

If you ever get the following error while using Excel Services to kick off a document to query the data from an Analysis Services database, you may wonder where the error come from and how to control it.

"Unable to refresh data for a data connection in the workbook."