Canon Global is divided into separate markets around the world. Each market has its own Canon web site. Canon distributes camera gear to the different markets. Gear is not always the same. For example, not every country in the world uses the same band of frequencies for public Wi-Fi networks.
In other words, you cannot register your camera at Canon USA because it was not purchases within the Canon USA market. You need to register your camera with the Canon site that serves your country of origin.
I know there are at least two Canon markets in Europe, Canon UK and and Canon Europe.