Problems launching Citrix XenApp 6.5 applications through CAG VPX 50 with the error: “Unable to launch your application. Contact your help desk with the following information: Cannot connect to the Citrix XenApp server. There is no Citrix XenApp server configured on the specified address.”

Problem

Ran into an issue the other day where I would have no problems logging into a Citrix XenApp 6.5 environment published with a Citrix Access Gateway VPX 50 (NS10.0: Build 73.5.nc) but noticed that whenever I tried launching an application, the status bar would get stuck at the following point:

After a few seconds, the following message is displayed:

Unable to launch your application. Contact your help desk with the following information:
Cannot connect to the Citrix XenApp server. There is no Citrix XenApp server configured on the specified address.

This error is consistent with published XenApp 6.5 applications and XenDesktop 5.6 VDIs.  No errors were logged on the XenApp servers or the Web Interface servers.

Solution

What ended up being the problem was that the Secure Access settings for the XenApp Web Site configured on the web interface server was configured with Direct for the Access Method:

Once this was changed to Gateway direct, applications began launching properly: