Recently a client had the following come up on their StoreFront Event Viewer

Failed to launch the resource ‘WTCITRIX.XenApp Desktop $S1-1’, unable to obtain a ticket from the configured Secure Ticket Authorities.

This is usually mimicked with an Error on the reciver end

Connection to “Desktop” Failed with Status (Unknown client error 0)

Make sure your Citrix StoreFront is configured with the STA details in the NetScaler Gateway section (remember you only need to use the STA in case of remote users, for which you would have to configure a NetScaler Gateway). They need to be the same also clear DNS cache if you have recently updated a DNS Record

Similarly the NetScaler itself is configured with the STA details.