We were in a situation were the “Workbook Activity – Chart” of the PowerPivot Management Dashboard was showing a red X. Our authentication provider is Kerberos so we applied the according SPN to our accounts. We also modified the web.config file of PowerPivot web service to support Kerberos delegation. We were also aware that ADOMD.NET in required on the server running the Central Administration site if you don’t want to have that specific red X. Our farm is under SharePoint 2013 and when you install the spPowerPivot.msi package from SQL Server 2012 it is installing ADOMD.NET package. We decided to install it manually to make sure it’s not an issue with the install but the error was still present. We went through the ULS logs and nothing was showing us that an issue is happening except this entry:
“System.Runtime.InteropServices.COMException: The file you are attempting to save or retrieve has been blocked from this Web site by the server administrators”
Again, when looking at the logs, we validated that the Central Administration site was configured in the “Trusted File Location” of the Excel Service. We decided then to look at the Event Viewer on the server and were hoping something interesting could be present. We were seeing an error but were thinking it is not related since our farm was not still live and our web applications were in NTLM to not break our actual production under SharePoint 2010.
We decided to refresh the page and noticed that the refresh triggered the error again. We then look directly in IIS for the authentication providers of the Windows authentication and found out that only NTLM was present. We added Negotiate and the issue was fixed. The issue was coming from a configuration that didn’t get applied when we changed the authentication provider of the Central Administration site. It was correctly applied in another environment so we probably faced a bug when we did our change. At least, everything is now running well.