When configuring Endpoint Encryption to use HTTPS using SEEMS Configuration Manager / Web Server Configuration, clicking on the Browse button to select a Server certificate results in an error message and no certificates are displayed:

You do not have any certificates in your local certificate store other than the one already associated with the Symantec Endpoint Encryption services website.

The server certificate is missing the Enhanced Key Usage attribute that contains:
Server Authentication (1.3.6.1.5.5.7.3.1)
Client Authentication (1.3.6.1.5.5.7.3.2)

Endpoint Encryption 11.1.2 and above.

Obtain and use a certificate that is valid for Server and Client authentication.