For security reasons, the 2-step authentication is now mandatory on most Apple accounts.
In order to access a given Apple account from a new device for the first time, you need to provide a verification code that has been sent to your device. 
To activate the 2-step authentication, please follow the process described in your Apple ID account page


Add a trusted phone number to your Apple Developer Account

  1. Sign in to your Apple ID account page: 
  2. Under "Security", click Edit 
  3. Under "Trusted Phone Numbers" add the trusted phone number. 
  4. A validation code is sent to the device associated with the phone number.
  5. Enter this code in your Apple ID account to validate the trusted phone number. 
You can add additional trusted phone numbers by following the exact same steps above.


One trusted phone number is mandatory, but we strongly recommend adding additional trusted phone numbers to your Apple ID account.
If your only trusted device is missing or damaged, you will not be able to receive the validation codes required to access your account in the future.


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