Particulars relating to higher-level service and wage type already exist

What causes this issue?

The data on a higher-level service and the wage type already exists in
one or more other service master records.

How to fix this error?

Please check your data. As a rule, a service is uniquely defined. More
than one lower-level service with the same wage type should therefore
not exist for a higher level service.

Error message extract from SAP system. Copyright SAP SE.