I am using the Magento2.2 version . I am using the class Magento\Sales\Model\ResourceModel\Order\CollectionFactory; to get the order collection.But getting the error

Fatal error: Uncaught Error: Call to a member function create() on null.

when I try to call create() function. Why I getting the error.please give a solution…

My code is:

<?php namespace {VendorName}\{moduleName}\Cron; use Magento\Sales\Api\Data\OrderAddressInterface; use Magento\Sales\Model\ResourceModel\Order\CollectionFactory;  class {class name} {     protected $  orderAddress;     protected  $  orderCollectionFactory;      /**      * @param OrderAddressInterface $  orderAddressInterface      * @param CollectionFactoryInterface $  collectionFactoryInterface      */     public function __contruct(          OrderAddressInterface $  orderAddressInterface,         CollectionFactory $  collectionFactoryInterface     )     {         $  this->orderCollectionFactory = $  collectionFactoryInterface;         $  this->orderAddress = $  orderAddressInterface;     }     public function execute()     {         $  dateNow = (new \DateTime())->format('Y-m-d H:i:s');        echo  $  days_ago = date('Y-m-d H:i:s', strtotime('-180 days', strtotime($  dateNow)));          $  orderCollection =  $  this->orderCollectionFactory->create()             ->addFieldToFilter('updated_at', ['lteq' => $  days_ago]);         echo $  orderCollection->getSelect()->__toString();         return $  orderCollection;      }   }