Could this be the reason? Because I did create a new Automatic Event Handling task using XML data that I retrieved from other task. If so, how do I fix this?
One issue that can cause a problem is that if the original Automatic Event Handling task was created with event and system criteria information specified during the creation of the task rather than using an existing event collection, then the query that is created for the original task is temporary and only exists while the original task exists. If that same event collection is used for the new Automatic Event Handling task, then that task can become invalid if the original task is deleted and the event collection is then deleted. Another problem is if the XML data retrieved from the original task is used to create a new Automatic Event Handling task after the original task is deleted. Then, an error of invalid or missing XML data is displayed.