If you use the single-version license code on more than one computer, there will be the Error 4104, because one license code is just for one computer ID. Therefore, if you tend to register the software on another new computer, we are sorry that you cannot do it. This is due to the limited License you got. The license code of Video Converter is unique and only for the first computer you register.
As for the family-version license code, you can use it on up to 5 computers but once it was registered in more than 5 PCs, 4104 will also occur.
As for the issue with error 4104 or you want to change the license on another computer, you can contact FonePaw customer support with your order details to help you reset the registration code for you soon.