slmgr /ato If still fails with 0x80072f8f , try phone activation:
slmgr /dti This shows an Installation ID. Then call Microsoft activation center. If your server is on a corporate network with KMS: Windows Server 2008 R2 Activation Error 0x80072f8f
slmgr /ipk <your_KMS_client_key> slmgr /skms <your_KMS_server> slmgr /ato If using MAK: slmgr /ato If still fails with 0x80072f8f ,