Hello Sohyeon,
I am a Microsoft user like you, providing solutions to community members; I am NOT a Microsoft employee.
Unfortunately Sohyeon, you've asked your question in the wrong place, as this community is for Microsoft users like yourself, you should assess Teams community for developers here https://learn.microsoft.com/microsoftteams/platform/feedback where you can get further assistance or probably report the issue to Microsoft Support at https://support.microsoft.com/contactus/
Hope this helps
-Stephen N.