With the Set-CsExternalCertificateFilePath cmdlet, you can now provide a path for a PSTN Gateway/SBC certificate. This allows automatic import of this certificate to the Mediation Server during installation. It’s now required that you specify the -Target parameter when setting the path for the external Edge certificate. If TLS is configured between the Mediation Server and the gateway, then you must run this cmdlet a second time to specify the path to the PSTN Gateway certificate and the target MediationServer. For more information, see Set-CcExternalCertificateFilePath .