On the M-Series appliance, if the Panorama > Support page doesn’t display support license details or the Panorama > Setup > Management page displays Unknown for the Serial Number even after you Register Panorama, perform the following steps:
Resolve Registration or Serial Number Errors
Record the Panorama serial number from the order fulfillment email that Palo Alto Networks sent when you placed your order for Panorama.
Select Panorama > Setup > Management and edit the General Settings.
Enter the Serial Number and click OK.
Click Commit, for the Commit Type select Panorama, and click Commit again.

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