Visual Studio 2017 can't apply a license key

[CClover]

Driving me crazy.

I've installed 3 different versions of VS2017 Professional from MSDN - community, 15 & 15.9 and I can't apply a license key.

After installing, I launch VS and I get this on a modal screen:

I have a MSDN y and need to use it.  I can't clear this modal and input the key.  If I "check for an updated license", I get this:

As far as I know  network/proxy settings are good.

The thing is, I expected to be able to enter the key from the Help menu, so what I'm seeing isn't making any sense.

I uninstalled the the Community version before installing professional.  I wondering if I'm dealing with an artefact of that install?

[#2]

Hi, thanks for posting your issue here.
However this platform is used for how-to discussions and sharing best practices for building any app with .NET.
Since your issue is a technical question, welcome to post it in Microsoft Q&A forum with the tag 'vs-general', the support team and
communities on Microsoft Q&A will help you for any technical questions.
Besides, it will be appreciated if you can share it here once you post this technical question Microsoft Q&A.

Best Regards,

Sara