Error: "Cannot build a trusted certificate chain for the certificate. Please make sure that you have added all the necessary CA certificates." occurs when attempting to select Control Center Certificate.
The certificate has been added in (Administration > Certificates > TLS & HTTPS Certificates)
The CA certificate or intermediate CA certificate has not been installed on the Symantec Messaging Gateway (SMG) to complete the certificate chain.
For successful SMTP/TLS or HTTPS authentication, there must be a complete "path" or "chain" from the client certificate to a CA certificate.
The SMG includes pre-installed certificates for the most common Certificate Authority vendors. If the Certificate Authority vendor is not listed underneath the Certificate Authority tab then you will need to install the CA Certificate.
Some certificate issuers require and provide an intermediate CA Certificate that is used for additional security. Intermediate Certificates will need to be installed underneath the Certificate Authority tab.
To add a CA certificate:
A status message appears at the top of the page to indicate success or failure.