Upgraded to Windows 10, now it's not legit?

[Windows Central Question]

A few months ago I finally gave into switching to Windows 10, and now after some time has passed, I had logged into my desktop and it says I am not running a legit version of Windows 10. I had followed your instructions with how I might fix it and I've tried to troubleshoot it but it tells me I have to connect to the internet to figure it out even though I am connected to the internet. Why did this happen and how can I fix it?