3386997 - Login error occurred when IAS and corporate IdP involved with error "Authentication error.The authentication process did not set an authenticated principal in the current thread" in IAS troubleshooting log.

• Login error occurred in the application side.
• Checking the SAML trace, IAS sent the error in the SAML response to the application.
      <Status>
          <StatusCode Value="urn:oasis:names:tc:SAML:2.0:status:Responder" />
          <StatusMessage>Failed to authenticate user.</StatusMessage>
      </Status>
• In the IAS troubleshooting log, there is error.
  ...message="Authentication error.The authentication process did not set an authenticated principal in the current thread. Id: ...
  
  
• Checking the SAML trace, in the SAML response from the corporate IdP to IAS, there is the Subject Name Identifier.
          <Subject>
              <NameID Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress">xxxxxx@yyy.zzz</NameID>
              ......
          </Subject>
• In IAS, the option "Use Identity Authentication user store" is enabled for the corporate IdP.

Identity Authentication.

IAS, IPS, corporate IdP, Azure AD, AD FS, ADFS, Failed to authenticate user,  Authentication error.The authentication process did not set an authenticated principal in the current thread , KBA , BC-IAM-IDS , Identity Authentication Service , Problem