You may receive an error "The server certificate is out of date. Connection dropped." If you login into your Web Interface server and check that the server certificate is still valid then you will notice that the clock on the computer (client) is set incorrectly. When the computer first connects to the Xenapp server there are checks to make sure that the security encryption certificates are current by comparing their expiration date to system time on the computer. This can happen if the date is set in the past or into the future.
To fix this issue, double click on the system time in the taskbar on the bottom right of your screen, click on the "change date and time settings" then change the date and time to current date and time.
You can now try to connect again. If it still does not connect, you may need to reboot your computer before making the connection to Xenapp server.