Hello @AnandShrivastava-322,
Thanks for reaching out.
Are you trying to add one of your Azure AD tenant as SAML/WS-Fed identity provider? if so then this is an expected behavior whereas Azure Active Directory users with an Azure Active Directory account can be invited via email and sign in without further configuration. They can also use Self-service sign up with User flows.
To lean more about Identity Providers for External Identities refer this article.
Hope this helps.
Regards,
Siva
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