Hello! Remember to log in with your forum username and password, not email! If that doesn't work, try temporarily changing your password on the forum to something else and checking whether that works for logging in to the game.
Additionally, if you are playing via the direct download on Windows, ensure that you have extracted the .zip file before attempting to launch the game.
Hey there! I enjoyed watching your first impressions playthrough of Legends of Equestria on Twitch. If you have any questions about the game, feel free to ask them in the official LoE Discord chat! It's a fair bit more active than the forums, and players sometimes organize activities there as well.