Embed Google Group

You can embed a group in a site and it is visible at the Google Site URL, but when the site is mapped to a domain the group can't be seen. You get 'Embedded groups are only supported on sites.google.com URLs'.  Instead of embedding the group you should make a link to it. Such as:  https://groups.google.com/g/k8omsowosso

Mapped to a domain: https://test.k8oms.net/group