I have a valid license installed. Why do I see Structure as Unlicensed or having Action Required in the Add-on Manager?
That may be so because Add-on Manager is not aware of ALM Works licenses. To verify the true status of your Structure license, check the Administration | Structure | License Details page. If it indicates the license is OK, you can safely ignore the status of the Structure license in Add-on Manager.
Structure supports two kinds of licenses — purchased via Atlassian and issued by ALM Works. For details, please see Setting Up Structure License.