This is a general purpose error that occurs when either the report server or a report authoring tool has invalid configuration settings. The error is usually accompanied by a second message that states the actual cause of the error.
The following list summarizes possible causes:
The RSReportServer.config or RSReportDesigner.config file cannot be found or read.
XML elements in either configuration file are missing or invalid.
Values for one or more XML elements are missing or invalid.
Registry settings are invalid.
If this error began to occur after you manually edited a configuration file, remove your changes and enter the previous value, or restore a previous version if you have a backup.
To review additional error message information that accompanies the rsServerConfiguration error, review the report server trace log files, which are located at \Microsoft SQL Server\MSRS12.<instancename >\Reporting Services\LogFiles. For more information, see Reporting Services Execution and Trace Logging.