Few of the panels in dashboard are reporting empty

Products

• DX Operational Intelligence

Issue/Introduction

One of our dashboard has empty panels, earlier it use to display the required data in the panels but that's not the case now. Some panels are reporting data.

Environment

Release : 20.3

Component : DX Dashboards

Resolution

Here is the list of some of the items that may cause this type of issue.

1- Some panels are using $datasource as part of the query. The dashboard configuration shows that datasource is not a defined variable, thus we can not use it in the dashboard query. The datasource needs to be change to environment as there is an environment variable defined in the dashboard.
2- On some panels, we see that there are multiple attributes defined. When reviewing the metric data via rest api call we do not see some of the attribute exist on the metric.
3- On some panels, we see that there is data for products, but product variable does not show those products. 
4- Some of the environments are not sending any data to DX SAAS. We see this when we do the rest api call.