All courses I load and then create an invite link get an error message after entering name/email.
If learners launch an invitation and receive an "Oops" error like the one below, there is a strong chance the learner is archived in your Realm. Archiving a learner removes access to all training originating from that Realm. You'll need to unarchive them in order for them to gain access. You can do this by navigating to the People tab and click "View Archived People".
If you have any questions, please contact us at firstname.lastname@example.org.