You can upload mappings for key mapping entities only.

What causes this issue?

You are attempting to upload mappings for value mapping functions or
codes, such as company code, business area or country code.

System Response

This is not supported with the <LS>Central Finance </> mapping tool and
the mappings for value mapping entities are <ZH>not</> uploaded to the
<LS>Central Finance</> system.

How to fix this error?

Select only key mapping entities, such as customer ID or G/L account for
uploading mappings from a CSV file.
You can still display or download mappings for value mapping entities.

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.