Yii2: Unknown Property Exception after adding column to table

Unknown Property – yii\base\UnknownPropertyException
Getting unknown property: app\models

What happens when you get an error Exception "Getting unknown property", after just added a field to the table in the database ?

1. Check your property name, was it correct?
2. Clear cache if you using cache. Yii2 will cache the table schema so if you change the table you need to clear the cache