The following error is displayed due to NetScaler backend server being unhealthy:
Cannot Complete Your Request
Verify the status of the backend servers. If any of the backend servers are unhealthy then troubleshoot and resolve the issue. For more information refer to CTX108960 - Probable Reasons for the Status of a Virtual Server Being Marked as DOWN on NetScaler. Once all backend server are functioning, you should be able to launch apps without any issues.
The backend servers load balanced by NetScaler is unhealthy.