Are you running an Enterprise version of Windows?

If so, a TAS licence is one that needs to connect to a special activation server that a company would set up when they buy the licence, in order to activate the operating system installation on both their static PC's and any laptops they may have. Usually only big companies use this type of licence as it saves them having to connect to Microsoft hundreds of times to activate all the PC's/laptops.

Can you connect to your office/workplace WAN and activate?

The other type used by companies (albeit smaller ones) is a MAK licence. The difference is the MAK licence can be activated multiple times, but the activation needs to be done via Microsofts normal activation procedure (like you would do at home).