How is the list of possible approver email options created?

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The list of possible addresses is generated by the Signing Authority and consists of the email address listed in the Whois information for the domain of the common name as well as a number of well known administrative addresses.

Please note that TierraNet is not able to alter this list. If you need to send the approver email to a different address, you will need to update the Whois information for the domain via its Registrar. Another option is to create a mailbox for one of the other possible approver email options and have the approval email sent there.