For some reason the Technical Preview (TP) version of Windows 10 Enterprise arrives with a KMS activation setting. Type in slmgr /dlv to get this info:

This fails as it cannot find a relevant KMS server in your test network to validate against (you are using a testing network right??!!!).
To fix this, you need to force a conversion to a Retail key and use a Microsoft Recovery Key to do so, follow these short steps:
- Open an Elevated command prompt
- Type slmgr –ipk PBHCJ-Q2NYD-2PX34-T2TD6-233PK
- You see a pop notifcation advising Product Key installed succesfully
- Windows will automatically activate

All sorted. Now check your activation status with slmgr /dvi again and you see this:
