how to create PO receipt along with attachment in fusion.Getting 403 forbideden error

Summary:how to create PO receipt along with attachment in fusion.

Please consider that attachment needs to be uploaded at Receipt line level.

Content (please ensure you mask any confidential information):

{    "ReceiptSourceCode": "VENDOR",    "OrganizationCode": "NA_MAIN_INV",    "VendorSiteId": 300000003250996,    "VendorSiteCode": "UAE",    "EmployeeId": 300000005116511,    "lines": [        {            "SourceDocumentCode": "PO",            "TransactionType": "RECEIVE",            "AutoTransactCode": "DELIVER",            "DocumentNumber": "PO2025-603",            "DocumentLineNumber": 1,            "POLineId": 300000012472567,            "Quantity": 1,            "DestinationTypeCode": "EXPENSE",            "attachments": [                {                    "DatatypeCode": "FILE",                    //"CategoryName": "REQ_INTERNAL",                    "FileName": "sample-7.xlsx",                    "UploadedFileContentType": "application/vnd.ms-excel",                    "ContentRepositoryFileShared": "false",                    //"Title": "sample excel-7",                    //"Description": "File attachment",                    "FileContents": "Ikl0ZW0gTnVtYmVyIiwiRGVzY3JpcHRpb24iLCJPcmRlcmVkIFF0eSIsIlVPTSIsIlNoaXBwZWQgUXR5IgoiSVRFTS0xMjMiLCJXaWRnZXQgQSIsIjEwIiwiRUEiLCIzIgoiSVRFTS00NTYiLCJHYWRnZXQgQiIsIjUiLCJFQSIsIjMi"                }            ]        }    ]}

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):