When attempting to print, the X2PA icon bounces in the dock and then closes; leaving the print job in limbo.

The problem is that X2PA was manually quit, forced to quit by another application or was removed as a startup item.

X2PA must reside in the dock and be running at all times. If it is not running printing will be halted. To fix this problem Stop printing in the control panel, re-launch the X2PA application and then 'Start' the printer from the control panel again.

If X2PA has been removed as a startup item, re-install the software.