Most of the times this error message shows up because the agent does not wait enough for the "ZOOMANDGO IS NOW CONNECTED" message to pop-up in Sabre's blue screen.

1. Ensure that required processes are running: open Task Manager (Press CTRL + ALT +DELETE keys in the same time for that) and verify that ZoomAndGo.Launcher.exe and javaw.exe are running.

2. Check if Sabre Emulator API is checked. Go to Sabre Red - Tools - Options - Advanced

3. Exit Sabre completely then proceed to the next step.

4. Kill both ZoomAndGo.Launcher.exe and javaw.exe from Task manager then restart ZoomAndGo.Launcher 

You can find the launcher in:

C:\Program Files (x86)\ZoomAndGo Inc\ITE Gateway Service\Sabre\gateway.service