Modern web app: enter your email address and password as usual. If a box labelled Authenticator code appears, type in the six-digit code from your app and click Sign In. After that, this browser shows the code box every time.

Classic web client: in the password box, type your password, a forward slash, and then the six-digit code. For example, if your password is correct-horse and the code is 492 817, type:

correct-horse/492817

A code works only once. If sign-in fails, wait for your app to show the next code and try again.

After ten wrong codes in a row, your account won't accept any code for fifteen minutes. Wait, then try again with a fresh code.