School admins can restrict what email addresses users may use to sign up for courses on Mimir Classroom at their school. To do this, sign into your Mimir Classroom account, and navigate to School Settings.
In your school settings, enable the restrict email domains setting and type in the domains that users are allowed to use to join a course at your school. Click update settings to save this change.
Now, new users will need to use one of your whitelisted domains in order to sign up for courses at your school.