After NetScaler Gateway authentication Web Interface redirects to a blank page (.../auth/agesso.jsp).

To resolve this issue, go to the Web Interface on Netscaler's site configuration and next to the NetScaler Gateway URL, click Add DNS Entry and proceed with the confirmation steps.

Problem Cause

The issue is caused when Netscaler is not able to resolve the Netscaler Gateway Vserver FQDN to Netscaler Gateway VIP IP.

CTX127967 - An Error Message is displayed when using a Wildcard SSL Certificate with Web Interface on NetScaler for Gateway Direct

Troubleshooting Methodology

1. Run the following command from NetScaler Command Line Interface to verify the logs from Web Interface:
   root@ns# cat /var/wi/tomcat/logs/localhost

   The following message is displayed in the logs:

   INFO: ERROR: Event Log ID: 18001 A communication error occurred while attempting to contact the Advanced Access Control authentication service at https://test.example.com/CitrixAuthService/AuthService.asmx.

2. Verify if the authentication service is running. The following message reported by the underlying platform is an nested exception:

   java.lang.NullPointerException. [Unique Log ID: 9ff1a8f3]

3. Verify the NetScaler Gateway URL on the Web Interface site configuration on NetScaler.

4. Ping the NetScaler Gateway FQDN from the NetScaler Command Line Interface to verify the NetScaler Gateway IP address.
   In this scenario it resolves to a different IP address and not the NetScaler Gateway IP address.