I'm unable to run simple task on Kubernetes.

SCDF version: 1.6.1.RELEASE

Kubernetes version: 1.11.2

dataflow:>app register --type task --name timestamp --uri docker:springcloudtask/timestamp-task:1.3.1.RELEASE
Successfully registered application 'task:timestamp'

dataflow:>task create task1 --definition "timestamp"
Created new task 'task1'

dataflow:>task launch --name task1
Command failed org.springframework.cloud.dataflow.rest.client.DataFlowClientException: Failed to resolve application resource: Docker Resource [docker:springcloudtask/timestamp-task:1.3.1.RELEASE]