There is no valid SMTP Transport Layer Security (TLS) certificate for the FQDN of %1. The existing certificate for that FQDN ...

There is no valid SMTP Transport Layer Security (TLS) certificate for the FQDN of %1. 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 %1 should be installed on this server as soon as possible. You can create a new certificate by using the New-ExchangeCertificate task.