Core Issue
This message might appear if the system is under a heavy load when either of these reports is generated. A heavy load can include tens of thousands of calls during the report period or the maximum number of skills cocfigured in the system.
Resolution
For a workaround to this problem, reduce the length of the report period, or reconfigure Contact Service Queues(CSQs) so that there are more CSQs with fewer skills each.
For more details about resolving Cisco Customer Response Applications (CRA) issues, refer to these documents: