January 27, 2009
The internal transport certificate is automatically generated at the Exchange Server 2007 hub transport server and is usually valid only for one year. Once the certificate expires, you will receive continuous event 12019 errors in your Edge transport servers that are subscribed via Edgesync.
Event Type: Error
Event Source: MSExchangeTransport
Event Category: TransportService
Event ID: 12019
Time: 4:46:34 PM
The remote internal transport certificate expired. Certificate subject: CN=<hub transport server>.
You can generate a new SMTP transport certificate on the Hub transport server by running the New-ExchangeCertificate cmdlet with no arguments.
This will automatically generate a new certificate. You then need to restart the Microsoft Exchange Edgesync service so that the Edge transport servers will be informed of the change.