Launching XenApp 7.8 application published through NetScaler 11 fails and throws the erorr: “Cannot connect to the Citrix XenApp server.Socket operation on non-socket”

Problem

You have successfully published applications on a XenApp 7.8 application server through a NetScaler but noticed that while you are able to log into the portal and view the published applications, you receive the following error when an application is launched:

Unable to launch your application. Contact your help desk with the following information:

Cannot connect to the Citrix XenApp server.Socket operation on non-socket

Attempting to launch the desktop of the application server throws the following error:

Desktop Viewer

The connection to “Citrix XenApp” failed with status (Unknown client error 1110).

Solution

One of the reasons why this error would be thrown is if you have not defined at least one STA server in the created NetScaler Gateway Virtual Server:

Notice that the screenshot below states No STA Server under the Published Applications section:

The error should no longer persist once a functioning STA server (the FQDN of your XenDesktop / XenApp Delivery Controller) is configured.