"NameID element must be present as part of the Subject in the Response message, please enable it in the IDP configuration"
What is this means?
And what do I need to do?
The error usually happens when the NameID element is missing from the SAML assertion retrieved from the identity provider (IdP). Configure the IdP so the NameID element is added to the SAML assertion.
Which IDP you are using. If you are using ADFS then you may check the below link and make sure you have the correct settings.