"Authenticity of the host’s SSL certificate is not verified" when trying to add ESXi Host to vCenter server.

Products

• VMware vCenter Server

Issue/Introduction

1. When trying to add a ESXi Host to the vCenter server, it flags out the error/warning "Authenticity of the host’s SSL certificate is not verified". 
2. On accepting the new certificate presented to the host by VMCA, you're able to complete the remaining steps to add the host succesfully.

Environment

VMware vSphere ESXi
VMware vCenter Server

Cause

When a newly installed host is added to the vCenter server, the issuer of that host's SSL certificate is "VM Installer". Therefore, the vCenter server (whose issuer is VMCA) is not able to validate the certificate of the host and most importantly its issuer (the signing authority). So, unless you accept the certificate presented to the host by the VMCA, it shall always flag "Authenticity of the host's SSL Certificate is not verified". 

Resolution

This is an expected behavior.

Accept the new certificate presented to the host by VMCA and you should be able to go past the error/warning message.