Excel Services Refresh Problem

When opening the workbook and refresh dataconnection sometimes excel can encounter problem playing the data again after refresh. Normal cases involves not setting Trusted Data Connection in excel services etc. But at 1 instance all the normal solution doesn't work for me and I found out this on the internet which seems to solve the problem

http://msdn.microsoft.com/en-us/library/cc514223.aspx


Windows Authentication Option
In Windows authentication mode, Excel Services attempts to use the Windows identity of the user who is logged on when authenticating with the external data source. Be aware of the following when choosing this mode:

Ensure Excel Services is configured to use the Delegation access model rather than the Trusted Subsystem model. You must set this configuration even if Excel Services and the back-end data source are running on the same server. To configure Excel Services to use the Delegation access model, use the Stsadm command-line tool. Type the following commands at a command prompt on the server, replacing sspname with the name of your Shared Services Provider (SSP):

stsadm -o set-ecssecurity -accessmodel delegation -ssp sspname

stsadm -o execsvcadmjobs

iisreset

If the external data source and Excel Services are running on separate servers, set up Kerberos delegation. You must do this to enable Excel Services to delegate the identity of the user who is viewing the workbook through the server tiers. For information about how to do this, see the Configuring Excel Services to Work with Kerberos later in this article.