공동 작업, 통신 및 효율성을 향상시키는 포괄적인 생산성 도구 및 클라우드 서비스 제품군입니다. 클래식 Office 앱 고급 Microsoft 365 기능과 결합하여 개인 및 비즈니스 요구 사항을 모두 지원합니다.
Dear jonghyun park1
Thanks for your reply and post in English.
Since Korean is translated by English so maybe there are some mistakes.
For the scenario you met, if you are using Microsoft365 for Business account, you will need to contact your IT admin to reset the authenticator. This is necessary because the multi-factor authentication (MFA) is still installed on your previous device, and for security reasons, it cannot be performed on a new phone without admin intervention.
Hope this can help. If you have any other consult or there is any update, please feel free to update me.
Have a nice day.
Katherine