Gii does not see the model when creating CRUD, what should I do?

Question

Yii

I recently discovered Yii2 and auto-generation of code using the Gii utility. However, I encountered such a problem that when generating CRUD Gii gives an error "Class 'frontend\models\Orders' does not exist or has syntax error." However, it exists and was generated by the same Gii.
Advanced version. The test example in the tutorial (which is with Country) reacts in the same way. I would be grateful for help in this matter.