Each adapter has a property named ReadyForRobotWork which controls if get next work is called when a robot activity is complete. All adapter's ReadyForRobotWork must be set to true or else no robot activities will be started.
This is how you prevent work from happening on start up before your adapters are ready and how you would stop work when you are having exceptions and want the all processing to cease.
The ReasonAdapterNotReady will eventually be displayed on Robot Manager (not there yet), so filling that in is a best practice if you are stopping processing.
If you set ReadyForRobotWork to false on any of your adapters they will stop receiving work. You just need to setup your process so that if there is an unrecoverable error on one of your adapters you set this value to false.