Got the same problem.
Code:
Bug during user login: Mercury.HabboHotel.Users.UserDataManagement.UserDataNotFoundException: No user found with ip (MY IP) and sso {sso}.
at Mercury.HabboHotel.Users.UserDataManagement.UserDataFactory.GetUserData(String sessionTicket, String ip, Byte& errorCode) in c:\Users\Jake\Downloads\MercuryNew\HabboHotel\Users\UserDataManagement\UserDataFactory.cs:line 57
at Mercury.HabboHotel.GameClients.GameClient.tryLogin(String AuthTicket) in c:\Users\Jake\Downloads\MercuryNew\HabboHotel\GameClients\GameClient.cs:line 158