Error message

For class 5A, you haven't configured any lessons. Add lessons to this class, or remove it from the class configurations.

What causes the error

You selected a class from the default list (e.g. 5A) and included it in a configuration, but no lessons were assigned to it.

How to fix it

You have two options:

1. Remove the class from the configuration if it's not needed – Go to the class configuration section, edit the setup, and deselect the class.
2. Add lessons to the class – In the lessons section, assign at least one lesson to this class.