Error code 0x803F7001 activating Windows inside Virtual Box

I had genuine Windows 7 and Windows 8, from some of which I have physical DVD boxes. Later it was upgraded automatically to Windows 10.

Recently I tried to make ISO with Media Creation tool, made ISO and install it into virtual machine within the same computer, I have original Windows 10. During installation it asked me for product key which I had none and answered "I have none".

Now inside Virtual Box I have activation problem. It says it can't activate and suggests to do something, including change product key. Inside properties of My PC of activated computer I see product ID which has different format and I can enter it into virtual machine.

Is it possible to overcome?

According to Microsofts help page, the error 0x803f7001 means that no valid license was found:

If you have a valid product key, use it to activate Windows:

Select the Start button, then select Settings > Update & security > Activation . Select Change product key, and then enter the 25-character product key.

Follow the steps and enter here your valid Windows 10 key. If you have upgraded your physical Windows PC, the license ONLY applies to the physical PC and not to any new VMs. Here you need to buy a valid license.