Hi Christian
It basically sais you don't have any records coming into SAP Solution Manager for this metric.
Since the extractor fetches the data from the configuration & change database, this would have to be your next step in the troubleshooting process.
Navigate to Solution Manager Administration workcenter
Click Infrastructure in left menu
Click on Administration - Configuration Change Database (in dropdown) in the right pane
Click on the tab Technical Systems and navigate or filter to the managed SAP system in question (for which the metric was empty)
Select the line of the managed SAP system
Scroll down to view the details of the stores for that managed SAP system
Filter down to Store Name "GLOBAL"
From there, try to figure out why the store is empty - check details / log etc here to see if you find hints to why the content is missing.
Best regards
Tom