Limit not to create new user with corporate email address

Summary

In Social sourcing SSO area we have turned on to limit not to create new user with corporate email address

Content

In Social sourcing SSO area we have turned on to limit not to create new user with corporate email address : Still We are able to create users -which causing us to manually clean up duplicate SSO accounts. Is there any other area we need to toggle to have this work correctly .

Talent Community:

Registration: Modular Registration, Choose Relationship,

Allow new user Sign Up with company Email Domain -  turned on .