The Default Identity Provider (IDP) is the primary Identity provider for your site. If you have set up Redirect to Default IDP, users will be redirected to this IDP for single sign-on (SSO). If you have enabled Domain Mapping and a user's email domain does not match any configured domains, the user will also be redirected to this IDP.
If you are still facing the issue, you can reach out to us at samlsupport@xecurify.com