SharePoint 2013: the SharePoint item being crawled returned an error

Problem

During routine check of your farm's crawl log, you discover five errors of type, 

The SharePoint item being crawled returned an error when attempting to download the item.

Checking the URL View of the errors, you find that each of them involves opening a Microsoft Office item, specifically, a OneNote item.  Clicking the URL returns the usual error page:

Sorry, something went wrong
An error has occurred on the server
Technical Details...

 Troubleshooting

1. Check ULS logs of primary WFE (WFE1) for the correlation ID: you find a number of entries associated with this correlation ID.  One in particular phrase in one of these entries catches your attention:

   System.ServiceModel.EndpointNotFoundException: There was no endpoint listening at net.pipe://localhost/SecurityTokenServiceApplication/appsts.svc that could accept the message. This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details. ---> System.IO.PipeException: The pipe endpoint 'net.pipe://localhost/SecurityTokenServiceApplication/appsts.svc' could not be found on your local machine.

2. Check status of Net.Pipe Listener Adapter service: reviewing server services, you find that this service is not running.  You start the service, and it starts successfully.
3. Check error message URL: you again attempt to navigate to the URL identified in the crawl error entry and this time you are able to view the page successfully.

Solution

• That phrase is indicative: if you see it in a ULS message, check the associated service.  If it's stopped, start it.

References

• AlsTechTips
• OWA 2013: Sorry, something went wrong
• SharePoint 2013: There was no endpoint listening at net.pipe...

Notes

• Two WFE farm, Windows NLB configuration.  WFE1 is NLB primary.
• I usually check the primary WFE first when finding errors like this one, since its more than likely the source of the error.