error when we upload the JPG file "An Illegal Attempt was made to upload a document"

Is it possible to upload the JPG file with binary data without file location from SAP to Opentext system by using the REST api with multipart/form-data

we have designed the logic to consume the rest API with multipart/form-data and trying to upload the direct binary data and getting the error as below-

"An Illegal Attempt was made to upload a document".

Can you please advise what is the exact root cause of this error

Thanks in advance