Check if the website you are logging in is as below.
|Previous cell phone number||
제한 적용 일시 :
Would you like to change the mobile phone number all at once?
* Information will be changed once [confirm] is clicked, so please decide carefully.
Change your security password regularly to prevent hacking incidents.
Easily predictable patterns, such as a combination of four consecutive or repeating numbers, the numbers included in your password and your email address and the last four digits of your mobile number are not allowed.
Please make sure to change your temporary (security) passcode in order to log in.