KMES Series 3, application version 6.3.1.3 or later, with the Registration Authority license enabled and initial setup steps completed (including loading a Platform Master Key and network configuration).
Allow outbound TCP port 2001 (default Host API port) from the Venafi TPP server to the KMES Series 3, specified by FQDN (for example, kmes.example.com) or CIDR (for example, 10.0.0.0/24).
TLS inspection or SSL proxies can break mutual TLS handshakes. Exempt the KMES FQDN(s) from inspection. Configure the KMES Series 3 with an FQDN so the exemption applies.