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Question: I installed the licensed version of the game and registered. When I enter my login, it says that such a login does not exist, even though it is indicated in my profile. What should I do?

You need to create an account on Ubisoft's servers. This is not the same as your in-game profile name. Go to the Ubisoft website and create an account there. Or, I think you could do it in the game... Although I'm not sure.