ADFS 4.0 IDP Initiated Sign On does not return 401 RRS feed

  • Question

  • I have an ADFS 2.0(Windows Server 2008 R2) setup for SAML WEB SSO and I am currently trying to setup the same in ADFS 4.0 (Windows Server 2016). I have a test that verifies that accessing idpinitiatedsignon.aspx?RelayState=RPID%3DmyRelyingParty.identifier.com returns 401 (Unauthorized)  and tries to authenticate after that. This is working fine with ADFS 2.0 but the new thing keeps returning 200 with a form to authenticate. When accessed from a browser and provided with the according credentials it authenticates successfully but I was wondering whether the return of 200 instead of the initial 401 is intentional or is there something that I am missing? Please note that I have the "RelayStateForIdpInitiatedSignOnEnabled" set to true both in "Microsoft.IdentityServer.Servicehost.exe.config" file and in the ADFS config (Get-AdfsProperties)
    Monday, March 18, 2019 7:26 AM