User identification can only be done using the information of an owner of the mobile phone.
( * Only Korean mobile phone number can be used for user identification. )
If you have a mobile phone under someone else's name, you will have to register your name as the actual user with the mobile service carrier, or go through the user identification using the information of the owner of your mobile phone.
If you go through user identification using the information of the actual owner of your phone, his or her information will be left in the user identification history. Thus, you may need to change the ownership to your name and then submit relevant documents to Kakao.
If you keep getting error messages during identification although you're using your own phone and have entered correct Kakao Account information, it is likely that the user identification service is experiencing temporary technical issues.
Should the user identification keep failing, please contact the service provider indicated at the bottom of the user verification page.