I have an issue where a security certificate expired the other day on our SBS server and i continually get this message in my event logs. I have followed the Microsoft article to renew the certificate with the same thumb print but the error still occurs.
I also have tried server restarts, importing the new certificate into the trusted certificate list but still the error appears.
It is an SBS 2008 server, please see below for full error message.
Event ID: 12016
User (If Applicable): N/A
Event Description: There is no valid SMTP Transport Layer Security (TLS) certificate for the FQDN of remote.domain.com.au. The existing certificate for that FQDN has expired. The continued use of that FQDN will cause mail flow problems. A new certificate that contains the FQDN of remote.domain.com.au should be installed on this server as soon as possible. You can create a new certificate by using the New-ExchangeCertificate task.
Event Log Name: Application
Event Log Type: error
Look forward to reading your comments