I was prompted to receive a One-Time Verification Code, what is this and why is it required?

For security purposes, we may ask you to enter a One-Time Verification Code to confirm your identity. This code is a unique series of numbers and/or letters that you can choose to receive via email or text. If prompted, please select how you wish to receive the One-Time Verification Code and then enter that code into the appropriate field. Please note that you will need a working Internet and/or data connection to receive a One-Time Verification Code. Your One-Time Verification Code will expire if you aren't able to enter it within 10 minutes. You can request another code by selecting your preferred verification option again. If you are unable to get a One-Time Verification code, please contact us via 'Chat with Us' on the American Express^® App or with Chat on your Online Account, or alternatively, by calling the number on the back of your Card.