Summing system input to calculate ratios for network adjustments

What causes this issue?

System input volumes for this network (gathered from allocation and/or
production and/or theoretical meters, and/or well completions) totaled
zero

System Response

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

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.