Can not create new or edit already existing tasks

[AaragBor]

The problem began about a week ago. I suddenly could no longer create new to do overs or edit any already existing ones. Whenever I click the create task button, I get the "Invalid form data" message:

And whenever I try to edit a task, I get forwarded to this page:
https://kirska.pythonanywhere.com/edit_task_action/5248/