If the 2-step verification code does not work properly, please try the following:
(1) Enter the latest passcode.
Start the 2-step verification application (Google Authenticator) that you have set up on your smartphone, and enter the "latest passcode" which is updated in a certain time (30 seconds). Please note that the old passcode cannot be used.
(2) Enter the passcode once it has been switched over.
If a certain amount of time passes during input, the passcode will change. Therefore, when entering a passcode, please wait for the passcode to be switched once and then enter the updated passcode.
(3) Check the automatic correction function of the clock
In order to use the 2-step verification application, the "time" of the device (smartphone/tablet) must be set correctly.
Please check if the automatic setting function of the device is turned on by yourself.
2-step verification app for previous devices
If you have changed your device and still have the 2-step verification app on your old device (smartphone/tablet), please try the passcode from the 2-step verification app.