The group administrator is on leave or has left the company and cannot hand over their administrator role. What should I do?

Change the group administrator using the following method.

Changing Group Administrator through Deputy Administrator's Proxy Operation
https://teachme.jp/8/manuals/36379562
* A group sub-administrator account is required.

If a group sub-administrator has not been set, or if there is no longer a user set as group sub-administrator, please contact support@teachme.jp with your Teachme Biz group number.

Manage group information (Web Browser)
https://teachme.jp/8/manuals/4929552