NameIDFormat not supported
Problem
In idp.xml and sp.xml, the NameIDFormat must be defined. This describes how to interpret the user ID sent by the IDP. Often, 'persistent' would be the semantically correct type (complete: urn:oasis:names:tc:SAML:2.0:nameid-format:persistent), however, 'persistent' NameIDs are only supported starting from IAM 6.0. Therefore, old IAM setups often use 'unspecified' or 'transient' are preferrable. When configuring the format, make sure to configure the same NameIDs both in the IDPs and the SPs metadata on both sides and make sure to update or restart the IAM instances after changing anything in the SAML XML files.