Even when an error has occurred in a device that is executing an activity, the workflow is continued as much as possible. When an error has occurred in an activity that is in progress in a device X, a server notifies the device X of an alternative device. The name of the alternative device (device Y) is displayed on the device X. The operator can send a job catalog request from the device Y to the server and select an aborted job from the provided job catalog. The server is notified of the selected job. When password authentication has succeeded, the device Y is permitted to continue the activity.