Exchange servers must use approved DoD certificates.

Server certificates are required for many security features in Exchange; without them, the server cannot engage in many forms of secure communication. Failure to implement valid certificates makes it virtually impossible to secure Exchange's communications.

Open the Exchange Management Shell and enter the following command: Get-ExchangeCertificate | Select CertificateDomains, issuer If the value of "CertificateDomains" does not indicate it is issued by the DoD, this is a finding.

Remove the non-DoD certificate and import the correct DoD certificates.