Error "Logon failed" - SSRS Service user account rights

I am facing a problem which is based on the restrictions on the domain of the customer. After deplyoing the report on the server we are getting the following error message in the report manager after executing (clicking) a report link:

Logon failed.

Logon failure: the user has not been granted the requested logon type at this computer. (Exception from HRESULT: 0x80070569)

I googled for that and it seems to be an authentication issue where some user / account is not granted to log on as service / locally, but the problems is better described than the solutions. Did anyone faced that problem so far ? Which account has to be granted what priviledges or permissions in Windows. We are using a SQL Server 2005 / Reporting Services 2005 running on the same machine whereas the virtual directories Reports and Reportserver are running in a separate Application Pool

Thanks,

Thomas

I 've exactly the same issue.

I thought that it's a delegation problem, because we work on different machines for SSRS and SSAS.

But it really looks like having a problem with the windows authenitcation on the SSAS server.