Why was a CC'ed email address not added to my Support ticket?
In most cases, this is a result of a setting in your Zendesk Support. If "anybody can submit tickets" is disabled under Admin icon () Settings > Customers, agents or admins need to add end-users to Support before end-users can submit a ticket.
If an email address is added as a CC on a ticket that is not associated with an existing user in Support, the CC will be ignored and not added to the ticket. CC's will also not appear on tickets if their accounts have been added to your CC blacklist. To check this click the Admin icon () in the sidebar, then select Settings > Tickets.
You can view CC'd addresses on a Support ticket by going to the initial comment, clicking the arrow, and selecting View original email. See Viewing the original email, including full HTML for more information.