Upgrade Windows 10 Home to Windows 10 Pro

I have a desktop running Windows 10 Home.
I would like to upgrade it to Windows 10 Pro using my Windows 7 Pro key.
On a Microsoft website it shows that I can use the following key:
VK7JG-NPHTM-C97JM-9MPGT-3V667.
I put this key in the Update & Security, Activation and change the Product key.
After several minutes a message came back stating that the key is invalid.
I tried again just using my Windows 7 PRO key and got the same results.
I the upgrade from Windows 10 Home to Windows 10 Pro invalid?

My Windows 10 Home is already activated.

I thought that if you have a Windows 7 Pro key, you can upgrade your Windows 10 Home to Windows 10 Pro using the Windows 7 Pro key.
On numerous sites it shows that you can do the upgrade form 10 Home to 10 Pro using the Windows 7 Pro key for the upgrade.

SALNARD said:

I thought that if you have a Windows 7 Pro key, you can upgrade your Windows 10 Home to Windows 10 Pro using the Windows 7 Pro key.
On numerous sites it shows that you can do the upgrade form 10 Home to 10 Pro using the Windows 7 Pro key for the upgrade.

The way to handle this is to disconnect the computer from the internet. Once the computer is disconnected from the internet, then change the Windows 10 Home product key to VK7JG-NPHTM-C97JM-9MPGT-3V667. As long as the computer is not connected to the internet, that will trigger the upgrade to Windows 10 Pro. You might get an error, but just reboot the computer and you will see you are on Windows 10 Pro, but it will not be activated. Reconnect to the internet and then change the product key to the Windows 7 Pro product key. If the Windows 7 Pro product key has not been blocked by Microsoft for online activation, it will activate it.

If the Windows 7 product key is blocked by Microsoft, does the OS go back to the Home version and continue to work?