Windows 8 Product Activation Failed

Hello, i purchased a windows 8 pro backup DVD. and I installed it into my laptop using clean install method. When i tried to install a product key, it said that "Error: 0xC004C003 The activation server determined the specified product key is blocked" . I wonder why ? I'm installing with DVD that I ordered, and I already inputted the serial number which is i received in Email.

Thanks