Hi. I have enabled MCD (Multiple Custom Domains) feature in my tenant, and going to use it for migration of customer base between domains. In my implementation Auth0 entities provisioning is done using Management API. Initially I had a single custom domain, and now have two.
One thing I noticed, is that now it’s required to provide auth0-custom-domain header on a set of API calls, such as Create User (if not provided, I get 409 Conflict). At the same time documentation doesn’t say much about how it impacts the behavior of the user that was created with a specific auth0-custom-domain header.
For instance, is it safe to create a user with domain_new and expect it will properly auithenticate on domain_old? Is there any impact on Enterprise SSO with SAML? Any other impact?
Also, once I enable multiple custom domains in my tenant, and start creating users with a specific custom domain mentioned in the header, I’ll have different types of user: those with custom domain and those without. What this will impact?