After you create a new Web application in your site collection, the Reporting Services service is not able to access all the databases that it must communicate with. You are not able to run reports from a document library in the new Web application, and you will see an error message that resembles "unexpected error". You also see an error message in the ReportServerService log file that indicates the database the report server service cannot access.
Run Reporting Services integration from SharePoint Central Administration. The Reporting Services Integration option is found in the Reporting Services area of the General Application Settings page.
Fernando Lugão Veltem edited Revision 1. Comment: added toc and tags
Ed Price MSFT edited Original. Comment: Updated the title case and added a horzontal line rule.