Getting '403 Forbidden' when trying to do Orderless Return using rest API

Summary:

We are trying to automate Orderless return process when we receive some items in our system. This is being done manually through UI.

We are calling below API to check if 'Orderless Return' is being performed through API, but we are facing '403 Forbidden' issues.

Content (required):

{

 "SourceSystemCode" : "FUSION_MOBILE",

 "SourceSystemType" : "EXTERNAL",

 "MaterialTransactionDetail" : [ {

 "InventoryItemNumber" : "XXXX",

 "OrganizationCode" : "XXXX",

 "SubinventoryCode" : "XXXX",

 "TransactionDate" : "2023-10-11T04:40:00-07:00",

 "TransactionQuantity" : 1,

 "TransactionTypeCode" : "ORDERLESS_RETURN",

 "TransactionUnitOfMeasure" : "Each"

                 } ]

}

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