The code is automatically sent as an email although you can switch to a US phone number ...
Make sure to leave the window open that asks you for the code. If you close this window and go back after you receive the code, the code will no longer be valid. If you need your browser to get your e-mail, open a new separate window, don't close. Also, make sure you are using the most recent code and not using a prior one. Every time that you ask for a code it cancels out all the previous ones that were sent and only takes the most recent. Please wait a few minutes after each code request to receive your email. It is not generated instantly.
You can also request your code via text message. To receive your codes through text please complete the following:
If you are still unable to get the code to work through text, choose I forgot my user ID or password and then choose I don't know my email address or user ID. You’ll be asked to provide some information about yourself, and then you’ll be asked a few questions verify your identity. If that method fails, you’ll get a phone number to contact customer support.