You attempt to launch a XenApp 6.5 application on an Android smartphone with the Citrix Receiver that is published through an access gateway but receive the following error
The requested application is not available at this time.
The error message presented is somewhat generic but one of the causes would be the communication between the STA and Web Interface server. I encountered this error when I mistakenly forgot to put in the proper port for the STA (changed from port 80 to 8080) in the web interface site for the Citrix Access Gateway. See the following post for more information:
Unable to launch XenApp 6.5 applications through an Access Gateway with event ID 30003 followed by 30205 logged on Citrix Web Interface Server