If firewall has both flow and syslog reporting enabled in GMS or firewall acquired via zero touch, GMS transition workflow would not create configuration to view historical GMS reports from NSM for such firewalls. However, you should manually create these configurations for these firewalls following procedure mentioned below.
To enable Reporting and Analytics for GMS Environments
Navigate to Manager View | Home > Firewalls > Inventory page.
Select the firewall on which Analytics is running and click the Ellipses icon below Action column and click on Edit Settings.
Under GMS/Analytics 2.5 Integration, enable the Enable View External Reports.
Select the added analytics agent from the GMS/Analytics 2.5 Agent drop-down menu.