A task targeting the Notification Server timed out and failed. The targeted agent shows as connected to a task server.
There was an unmanaged duplicate computer resource with the same host name targeted instead of the intended managed computer resource.
Troubleshoot where the duplicate, unmanaged, computer resource is coming from and if needed, create a Computer or Resource Merge task to merge the two computer resources.
Alternatively, prevent the import of the duplicate computer resource and delete the existing unmanaged computer resource.