For setting up WritebackExtreme SSO there are some necessary attributes to be set, with the exact name convention:
|id||user.objectid||The unique identifier on the IdP and/or being used by Tableau as an identifier.|
|username||user.email||This field can be the same as the Tableau username.|
|display_name||join(user.first_name, user.surname, user.last_name)||A joined field to create a Display name for Writeback. Can be first_name only|
The Example column is based upon Azure IdP, so this information can be different per IdP implementations like Ping, Okta, etc.
Please note that the attribute names should be exactly the same as described above.