There are several reasons why the dashboard might be empty. In your case, there are no errors in the logs, but the data cannot be retrieved. We have encountered similar situations before.
Previously, the issue we encountered was caused by a mismatch between the time the data was recorded and the time used for display. We are still not entirely sure how this discrepancy occurs. However, it can typically be resolved by clearing the historical data.
You can try clearing the data in the settings. Please check if the dashboard remains empty after doing so. In our experience, after clearing the data, the issue of the dashboard failing to retrieve data usually does not reoccur.