The web browser may display the message, Error: Page not found, when you click on a ticket attachment.
This can occur when a load balancer is configured and an alias to Service Desk is being used to hide the hostname and port number from external users.
Although the alias name set at the load balancer is accessible to external users, it cannot be found by the local DNS, so including this alias in the repository name does not resolve the problem.
Set the servlet path to a URL that is reachable by the external users.
For example, set it to http://www.servicedesk.com:8080/CAisd/UploadServlet where www.servicedesk.com is the hostname alias set on the load balancer for Service Desk.
Be sure to configure the load balancer to process Tomcat requests from the Tomcat port, usually port 8080.