In Aria Operations UI capacity section the capacity has a gray question mark and says "Capacity data is not available"
Aria Operations 8.x
Capacity is shown as UNKNOWN when there is a collection issue, often when a certificate has been updated.
From the Aria Operations user interface click Data Sources > Integrations
Select the particular adapter and go to edit settings
Click Validate Connection
A prompt comes up asking the user to import the associated certificate. Click OK. Then save the adapter.