The error is displayed when we access the Web Interface url configured with Secure Gateway. Create a Direct site and it should work fine.
This issue is most likely related to compatibility between Secure Gateway 3.3.0 and Windows Update.
Add Nameserver or Address record
NetScaler GUI > Configuration > Traffic Management > DNS
CTX109556 – How to Enable NetScaler Appliance to Use DNS for Resolving the Hostnames to IP Addresses.