I had that problem. Make sure you are capitalizing your username & password exactly how you did when you signed up. Username is case-sensitive just as password is.Why is it I have to log in to get boxes?!? Usps can't you just send them to me!!! I have 2 packages to send but no boxes!!! I can't even log in on cusps because it says I don't have the right password!! I just made it today!!!