Hi Richard,
Were your SPS and Policy server configured to support Session Assurance using Device DNA functionality?
Do you intend to use Session Assurance feature? I think Session Assurance was shipped by default in SPS.
What is exact version of your SPS and policy server?
This error seems to be Session Assurance feature related. You may choose to ignore the error if there are no any other functional problems observed.
If you do not use Session Assurance feature, by disabling it ("Advanced Auth" part) from SPS server.conf file should resolve it.
If you do use it, then you need to follow the SSO documentation on Session Assurance, and have everything setup by the book.
Thanks,
Hongxu