Copy the link from the browser of a Pulse Metric and paste it below.
PowerKPIs is using the embedded version of Tableau Pulse. Therefore it only works when the workbook is published to Tableau Cloud.
To test: Publish the workbook to Tableau Cloud.
To add a Pulse metric, head over to the Metrics section, open one of the KPI Metrics and scroll to the bottom. Paste the URL of the Pulse Metric here.