Used by activity workers, Task states using the callback pattern, and optionally Task states using the job run pattern to report that the task identified by the taskToken failed.

For an execution with encryption enabled, Step Functions will encrypt the error and cause fields using the KMS key for the execution role.

A caller can mark a task as fail without using any KMS permissions in the execution role if the caller provides a null value for both error and cause fields because no data needs to be encrypted.