Analysis for Office SSO issues (HTTP request unouthorized, SSO ticket expired)

Hello,

We configured Windows AD SSO and SAP BW SSO, both working fine so far with BO Analysis for office (BO 4.1 SP1 Patch3, Analysis for Office 1.4).

Unfortunately after a while of inactivity (around 30-60min) in the excel client, the users receive the following error message when inserting a new query in analysis for office. I assume that it's a timeout issue, but I already increased the session.timeout-parameter in dsws.properties.

Any other ideas what the reason for that error could be? Thanks!

Log Entries:

The HTTP request is unauthorized with client authentication scheme 'Anonymous'. The authentication header received from the server was 'Negotiate'.The remote server returned an error: (401) Unauthorized.

and also sometimes

>> General .NET Exception:

System received an expired SSO ticket

   at SAP.Middleware.Connector.RfcConnection.ThrowRfcErrorMsg()

   at SAP.Middleware.Connector.RfcConnection.ReadBytes(Byte* buffer, Int32 count)

   at SAP.Middleware.Connector.RfcConnection.ReadRfcIDBegin(Int32& length)

   at SAP.Middleware.Connector.RfcConnection.ReadUpTo(RFCGET readState, RfcFunction function, RFCID toRid)

   at SAP.Middleware.Connector.RfcConnection.RfcReceive(RfcFunction function)

   at SAP.Middleware.Connector.RfcConnection.ConnectAsClient(RfcDestination destination, Boolean forRepository)