Status of CC system does not allow rating

What causes this issue?

The state of the SAP Convergent Charging system does not allow the price
to be queried. The database or the instance is possibly shut down.

System Response

The SAP Convergent Charging system does not return a price for the
consumption item.

How to fix this error?

Notify the administrator of the SAP CC system.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.