Data Refresh Failed

Problem Description: Data Refresh Failed You have configured Microsoft Office SharePoint Server 2007 to enable workbooks load in Excel Services. You have stored your data connection in a trusted data connection library and your Excel 2007 workbook in a trusted file location. You open the Excel 2007 workbook and you apply a filter or you choose to Refresh All Connections. Following error message is appearing: Unable to retrieve external data for the following connections: Connection_Name The data sources may be unreachable, may not be responding, or may have denied you access. Verify that data refresh is enabled for the trusted file location and that the workbook data authentication is correctly set. Refreshing all connections or filtering with an administrator account works without problem.