By default the remote errors property in SQL Server Reporting Services is set to false, which means error messages in a multi-server environment aren't very detailed.  By enabling remote errors, you will get additional error information returned which is more useful than this:

For more information about this error, navigate to the report server on the local server machine, or enable remote errors.

Option 1 to Enable Remote Errors - DB Engine

1.  Connect to the database engine in SSMS and navigate to the ReportServer database.

2.  Query the ConfigurationInfo table to get familiar with it.  Issue the following query:

USE ReportServer

GO

 

UPDATE ConfigurationInfo

SET Value = 'True'

WHERE Name = 'EnableRemoteErrors'

 

Option 2 to Enable Remote Errors - Report Server

This option applies to SQL Server 2008 and newer.

1.  Connect to Reporting Services in SSMS.

2.  Right-click on the server node and go to Properties.

3.  On the Advanced page, set the EnableRemoteErrors property to True. 

 

Option 3 to Enable Remote Errors - Script

This Technet article also describes how to enable remote errors using a script, if you'd prefer to handle it using a RSS (Reporting Services Script), which is executed using the RS utility.