https://userapps.support.sap.com/sap/support/knowledge/en/3127573
3127573 - SAML2.0: Error "SAML2_RESPONSE is not signed" for ABAP authentication | SAP Knowledge...
While performing a SAML 2.0 authentication to ABAP system, it fails. The following information can be verified in ABAP SAML Traces: SAML20 SAML20...