How to activate Windows Server 2016 using MAK key and no local KMS?

We have a very small virtual environment with only two Server 2012 VMs. We just purchased a license (local government entity) for Windows Server 2016 in order to add another VM to our stack. I'm having trouble activating the new VM. We are not using a KMS because that seems like a lot of extra work for such a small group. But when I attempt to activate the new 2016 server with the MAK key provided from microsoft.com/licensing, it says the system must connect to a local licensing service. Then it fails with 0xc004e028 error: "We can't activate Windows on this device right now. You can try activating again later or go to the store to buy genuine Windows."

What is the correct procedure to activate Windows Server 2016 using a MAK key and Microsoft's activation servers (not local), avoiding the need for local KMS infrastructure?

Thanks

Error 0xc004e028 is, according to Microsoft:

You might see this error if you try to activate a device that is already in the process of activation. Your device should be activated after the first request is completed.

Sounds to me like your server is just pending activation. I'd give it an hour or so, reboot, and if it's not activated, try again.