Error raised when trying to configure SSRS and HEAT in a SSL environment based on Kerberos authentication.
Following infrastructure is used:
Having just Kerberos authentication enabled:
Edit SSRS config file and add <RSWindowsNegotiate/> or the other value about only Kerberos
Create SPNs for http (FQDN and if used ALIAS). The user specified should be the user which is used in the Application Pool HeatAppServerAppPool
Create SPNs for MSSQLMSSQLSvc with the FQDN (or ALIAS)
ServiceUser must have the “trust this user for delegation to any service (Kerberos only)” activated or the even higher restricted version on the bottom of this value.