Azure b2c iframe embedded sign in 400 bad request.

Along with the local account (email and password) we use Entra ID as sign in option. The Entra ID used for sign in is from another tenant.
<Description>Login with your Entra ID account</Description>

<Protocol Name="OpenIdConnect"/>

<Metadata>

			<Item Key="METADATA">https://login.microsoftonline.com/myentradomain.com/v2.0/.well-known/openid-configuration</Item>

			<Item Key="client_id">myclientid</Item>

			<Item Key="scope">openid profile</Item>

			<Item Key="response_types">code</Item>

			<Item Key="response_mode">form_post</Item>

			<!--<Item Key="response_mode">query</Item>-->

			<Item Key="HttpBinding">POST</Item>

			<Item Key="UsePolicyInRedirectUri">false</Item>

</Metadata>
Since the iframe is only allowing SAMEORIGIN the login.microsoftonline.com is being blocked by the browser. What would be solution to this problem? Is there an option to use Entra ID with MFA (Octa and Microsoft authenticator) inside the iFrame. Or I would need to redirect the request to top level window?
Thank you!