title: Scrapy: Unable to fetch information on Urls that reached the max retries
body: <p>I'm getting a lot of 503 from a site I am <strong>scraping</strong> with Scrapy and I can't get it to record a list of all the failures.</p>
  <p>I've enabled the Retry module using RETRY_ENABLED = True and set RETRY_TIMES = 2 for testing purposes.</p>
  <p>I've added the from_crawler class method and registered two callbacks but none are being called.</p>
  <pre><code>@classmethod
  def from_crawler(cls, crawler, *args, **kwargs):
      spider = super(MySpider, cls).from_crawler(crawler, *args, **kwargs)
      crawler.signals.connect(spider.item_error, signal=signals.item_error)
      crawler.signals.connect(spider.item_dropped, signal=signals.item_dropped)
  
      return spider
  
  def item_error(self, item, response, spider, failure):
          self.log(&quot;************************ ERROR ********&quot;, logging.ERROR)
          self.log(item, logging.ERROR)
  
  def item_dropped(self, item, response, exception, spider):
          self.log(&quot;*********************** DROPPED *********&quot;, logging.ERROR)
          self.log(item, logging.ERROR)
  </code></pre>
  <p>The callbacks are not called when a URL failed with or without exception</p>