Problem statement
This article addresses the situation in which an admin is not able to update specific user emails with custom DB import OFF. The update results in error:
400: User with old email does not exist in Auth0 database
Solution
This error appears when the user has logged into Auth0 using the given email, and then the user’s email has been changed/updated in the legacy DB (for the same user_id ).
Now, since the import mode is OFF, and there is no user profile in the legacy DB against the email with which the user logged in for the first time, the update results in the observed error.
Since the user profile in Auth0 has a different email than the one in the legacy DB, try logging in with the new email (present in the legacy DB for the same user_id).
This should sync the user profile in Auth0.