These instructions are of relevance if you have a server certificate for the Guest Server for installation that has been issued by an intermediate CA. These instructions are valid for Guest Server 2.0.x only.
NGS use certificate from intermediate CA server but client managing NGS only has root CA certificate trust installed. Hence NGS will have to send the full certificate chain to allow client validate the server NGS certificate.
NOTE: This is not a official Cisco document and you use it on your own risk.
Best regards
Roger Nobel