Why does Microsoft® block certain Office product keys?
When Microsoft® discovers that a key has been leaked, stolen, misused, or is a false key, Microsoft® may block that key to keep it from being improperly used. If you receive a failure message indicating that the key used to install your copy of Office has been blocked, and you believe you have received the message in error, contact your system administrator or the place from which you purchased Office to resolve the issue.
