When you implement the Microsoft SQL Server 2014 Reporting Services (SSRS 2014) Service Application in a Microsoft SharePoint Server 2010 or Microsoft SharePoint Server 2013 cross-farm environment, you cannot render reports from the publishing farm by using the Report Viewer Web Part on the consuming farm. Additionally, you may receive an error message that resembles the following:
The item '<URL>' cannot be found. --->
Microsoft.ReportingServices.Diagnostics.Utilities.ItemNotFoundException: The item '<URL>' cannot be found.
Service pack information
To resolve this issue, install Service Pack 1 for SQL Server 2014.
For more information about SQL Server 2014 Service Pack 1 (SP1), see bugs that are fixed in SQL Server 2014 Service Pack 1.