When an author attempts to Send E-mail Invitations out from a coaching course; it does not provide a URL link in the e-mail. Instead of a link, the author will see 'Course has external content and URL is not provided'.
This is expected behavior, as coaching courses are not considered source 'content' to link back to. The links are tied to the specific user enrollments; so we would be unable to provide a generic link for general access. The author would need to send 'enrollment e-mails' from the course enrollments page; with the notification enabled for the link to populate.