So I am a 1.0 player and have had a Square Enix Account for a long time. Turns out that if you have not merged your old Square Enix North America account with the newly Square Enix Membership then you will get "Error 3" EVERY time! If you are having trouble your Accounts may not be synched!!:D
Go here to link your accounts https://membership.square-enix.com/sea_migration/login