Sometimes you can face this error even if you set up security policy properly:
The class that raised this error extends SRSReportDataProviderBase.
public class AnkPriceListDP extends SRSReportDataProviderBase
public void processReport()
The method is an entry point for the SysOperationProcess class.
The access to run this method is also checked in the SysOperationProcess class. I couldn’t set up the access exactly for this method. So I fixed the problem by granting access to execute this method in the privilege’s Permission.ServerMethods node.