Failure: Invalid merchandise description of package (120623)

Can anyone help me on below issue?

I am receiving the below error message after the implementation return service.
**_Failure: Invalid merchandise description of package (120623)_**

**Code what we used.**
if (isset($return_order) && $return_order==1) {
$returnService = new \Ups\Entity\ReturnService;
$returnService->setCode(\Ups\Entity\ReturnService::PRINT_RETURN_LABEL_PRL);
$shipment->setReturnService($returnService);
}

If I also use the below code then it gives as mention error

**_Failure: Shipment/ReferenceNumber is not allowed for this shipment (120541)_**

**Code what we used.**
if (isset($return_order) && $return_order==1) {
$referenceNumber->setCode(\Ups\Entity\ReferenceNumber::CODE_RETURN_AUTHORIZATION_NUMBER);
$referenceNumber->setValue($shipping_reference_number);
} else {
$referenceNumber->setCode(\Ups\Entity\ReferenceNumber::CODE_INVOICE_NUMBER);
$referenceNumber->setValue($shipping_reference_number);
}
$shipment->setReferenceNumber($referenceNumber);

If I also use the below code then it gives as mention error

**_Failure: Invalid merchandise description of package (120623)_**

**Code what we used.**
if (isset($return_order) && $return_order==1) {
$referenceNumber->setCode(\Ups\Entity\ReferenceNumber::CODE_RETURN_AUTHORIZATION_NUMBER);
$referenceNumber->setValue($shipping_reference_number);
} else {
$referenceNumber->setCode(\Ups\Entity\ReferenceNumber::CODE_INVOICE_NUMBER);
$referenceNumber->setValue($shipping_reference_number);
}
$shipment->getPackages()[0]->setReferenceNumber($referenceNumber);