In chapter 4 (around pages 97-99) we are shown how to create a new output formatter which will render the page in Yaml syntax, but it results in:
This webpage is not available (Chrome, with a console error of 'net::ERR_INVALID_RESPONSE')
File not found (Firefox)
In chapter 4 (around pages 95-96) we are shown a throwaway snippet as an example of outputting a view in JSON format which results in a fatal error:
PHP Fatal Error – yii\base\ErrorException Class 'app\controllers\Response' not found
In chapter 3 (around pages 72-73) we update the layout file to use some assets to make our pages look better, but this can result in a fatal error:
PHP Fatal Error – yii\base\ErrorException Call to undefined method yii\helpers\Html::csrfMetaTags()
In chapter 2 (around pages 54-56) we should now be able to save a record using our new form but you may run into some errors such as being redirected to the wrong page after submission and an unknown method error.
In chapter 2 (p53) we should be able to view our newly created form, but it's likely (if you are just following along with the book) that you will be getting errors such as 'Class 'app\controllers\CustomerRecord' not found' when trying to view the page.