Sagemaker notebook doesn't run on Job schedule

Hello. I created a Notebook Job Definition, scheduled to run every hour. According to the status it is "Active". Whenever I manually trigger the job with the "Run Job" button, it creates a new Notebook Job and runs successfully. However, the notebook never runs on the schedule. It should execute every hour, but instead only executes when manually triggered.

Is there anything I need to do for the notebook to obey the schedule? Thanks,