By default, a distribution list is enabled for all users in the organization. Administrators can disable distribution lists by clearing the appropriate Enable check box. Disabling distribution lists minimizes the risk of users sending spam emails.
Users are not notified when a distribution list is enabled or disabled. If a distribution list is disabled, the name is not automatically completed as a user types it in. If a user sends email to a disabled distribution list, the email is bounced back to the inbox of the sender.