Login_hint is not working for Microsoft Azure - SAML connection

We are trying to forward email from SDP (Auth0) to IDP by adding ‘login_hint’ when connecting to Microsoft Azure AD - for SAML Enterprise connection, as suggested in this post, but this isn’t working.

AADSTS7500525: There was an XML error in the SAML message at line 1, position 529. Verify that the XML content of the SAML messages conforms to the SAML protocol specifications.

We also tried decoding SAML Request to XML. XML format is correct. Is this issue specific to IDP?

@lihua.zhang, Can you help us with this?

We are having the same requirement. For Azure AD via SAML, the login hint can be passed as a query parameter to the SAML URL, e.g. https://login.microsoftonline.com/<tenant-id>/saml2/?login_hint=john.doe@contoso.com

However, I think there is no method to configure or modify this in Auth0.