Windows 10 activation failed 0xC004C008

I just built a new PC but I didn't buy a new Windows 10 license. I have a laptop that came with windows 10 so I uninstalled the product key from the laptop with the command

slmgr /upk 

and installed Windows 10 on the new computer with the code I extracted from the laptop. It wokred during installation but now it says that the product key is used by another device, which it isn't since the 'Activate Windows' watermark is present in the laptop.