Unable to process SAML request

Issue

• Some users are unable to login via SAML
• Steps to reproduce:
  • Login User for the first time
  • The user gets logged-in successfully
  • Now, log out and try logging in again
  • Result: Throws unable to process SAML request error on UI, and Invalid NameId Policy error in the logs.

Environment

• Liferay DXP 7.0+

Resolution

• Check the NameId provided in the IDP connection details and change it to unspecified.
• Now try to login again, this should enable the users to login.