What are the likely causes of this?

A hotel chain deployed ClearPass Guest. When hotel guests connect to the Guest SSID, launch a web browser and enter the address www.google.com, they are unable to immediately see the web login page.

What are the likely causes of this? (Select two.)
A . The ClearPass server has a trusted server certificate issued by Verisign.
B . The ClearPass server has an untrusted server certificate issued by the internal Microsoft Certificate server.
C . The ClearPass server does not recognize the client’s certificate.
D . The DNS server is not replying with an IP address for www.google.com.

Answer: BD

Explanation:

You would need a publicly signed certificate.

References: http://community.arubanetworks.com/t5/Security/Clearpass-Guest-certificate-error-for-guestvisitors/td-p/221992