To retrieve a secure email that has expired, you need to access your journal, described in How do I view the sent items log from Outlook?, from the Secure Exchanges settings on the Outlook ribbon.
Next, follow these steps:
You will receive two emails in your Outlook inbox: the first containing the email you requested to be retrieved, and the second containing a report of your retrieval request.
Our team is available to assist you. Write to us at support@secure-exchanges.com