Uploading wrong scans
I accidentally uploaded model solutions written on Zesje exam paper. This caused some trouble when I wanted to send emails to the students. When I tried to send the emails I got the error message "All submissions must be validated before sending emails." I solved this by creating a fake student with a nonexistent email and assigning that submission to that student. Then I could send emails again. This issue is about implementing a better solution for the future.