Volume license activation (KMS method) cannot activate Windows 7 Pro. on Optiplex 3010, 7010, 9010 ?

My enterprise has perchased many licenses of Windows 7 Pro. including KMS activation license. Recently, we bought a set of Opliplex 3010 , 7010 & 9010 PCs, nearly 500 PCs. I tried to re-deploy OS and many enterprise APPs to these PCs through network , using Microsoft SCCM. 

The OS image I used in SCCM is Window 7 Pro Volume License Edition. But the KMS method cannot activate Windows 7 Pro. on Optiplex 3010, 7010, 9010 in our LAN . After deployment, the PCs telled that the the volume license key is invalid, Windows cannot be activated.

How to solve the issue? Thanks!