Why can't Apple's 6P mobile phone download the APP, and it will pop up to receive the verification code of the mobile phone? However, no text message came.

Apple mobile phone 6P is used to judge your mobile phone number, right? If you change your new mobile phone number, you won't get the authentication code at all. You have stopped using this number. Can the old mobile phone number be authenticated? If the old mobile phone number has been deactivated, you will not be able to receive the argument code and download the app. Your Apple phone will pop up the Apple account ID. Prompt the system to detect that you have changed your mobile phone number and log in again. What's the problem? You can keep asking me.