IDPv3.1.2: SAML2 AttributeQuery processing fails with Message context was not authenticated

[Guenther Schreiner]

Hello,

 whereas our configuration for SAML1 works well avoiding an AttributeQuery
 with the includeAttributeStatement, the SAML2 processing fails during the
 AttributeQuery with
 >> WARN [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:182] - Profile Action WebFlowMessageHandlerAdaptor: Exception handling message
 >> org.opensaml.messaging.handler.MessageHandlerException: Message context was not authenticated 
 
 Any idea to avoid this situation?

Regards,
-Guenther