A Company Is Moving All of Its Web Applications to an SSO

Multiple Choice

A company is moving all of its web applications to an SSO configuration using SAML. Some employees report that when signing in to an application, they get an error message on the login screen after entering their username and password, and are denied access. When they access another system that has been converted to the new SSO authentication model, they are able to authenticate successfully without being prompted for login. Which of the following is MOST likely the issue?

A) The employees are using an old link that does not use the new SAML authentication.
B) The XACML for the problematic application is not in the proper format or may be using an older schema.
C) The web services methods and properties are missing the required WSDL to complete the request after displaying the login page.
D) A threat actor is implementing an MITM attack to harvest credentials.