Please change the administrator using the following method.
▼Change the administrator via Sub-administrator proxy operation
https://teachme.jp/8/manuals/51166988
※A Sub-administrator account is required.
If you have not set up a Sub-administrator, or if there are no longer any users assigned as Sub-administrators, please contact support@teachme.jp along with your Teachme series Group number.
▼How to check your Group number
https://teachme.jp/8/manuals/51167005