Capture DFF Fields during material transactions through REST Service

Hi Experts,

We are trying to upload the DFF Fields using REST Service for INV_MATERIAL_TXNS but getting the below error

Please help to find the correct attribute to use the REST service.

We are following the below document from Oracle but still no luck:

Capture Descriptive Flexfields During Material Transactions Through the User Interface, a REST Service, and File-Based Data Import

Thanks,Srikar