Solution: Clear the application cache. Yii caches configuration data. Run: php yii cache/flush-all. Additionally, verify that the path @app/sets_4047/templates/ actually exists and is readable by the web server user.
The "Sets 4047" dynamic relation loader can be resource-intensive if you have 40+ relations. After installation, optimize by: webe gigimodel sets 4047 install
Solution: You forgot Step 4. Ensure the runtime_sets folder is copied to your models/ directory, and that your namespace matches the PSR-4 autoloader. Solution: Clear the application cache