It can take up to 24 hours for data to update. Please check if it works after 24 hours later. Morever, The usage metrics report only includes reports or dashboards that have been accessed in the past 90 days. If a report (or dashboard) doesn't show up, likely it hasn't been used in more than 90 days. Please check if the report or dashboard is used in the past 90 days.
For further information, you may refer to the document .
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