The reason why the registration problem exists even after keying in several times, is that the application cannot save the authenticated license information to the Folder HelpDesk Outlook folder. As the license info cannot persists, you are asked again and again to key in.
The solution to this issue is that the registration should be performed by a helpdesk user who has owner rights over the Folder HelpDesk Outlook folder.
If you are sure you had owner permission when you keyed in the registration key and e-mail address, the permission mechanism for the folder has probably gone awry. In this case, you need to reset your permission to none, and then after 5-10 minutes, reassign owner’s rights. Perform the key-in and you should be good to go.