UPS Rate API missing or invalid field

I am trying to setup UPS Rate API for one of my app, my data looks like:

{
    "RateRequest": {
        "Request": {
            "RequestOption": "Rate"
        },
        "CustomerClassification": {
            "Code": "00"
        },
        "Shipment": {
            "Shipper": {
                "Name": "**********",
                "ShipperNumber": "*****",
                "Address": {
                    "AddressLine": "7550 N Croname RD STE 500",
                    "City": "Niles",
                    "StateProvinceCode": "IL",
                    "PostalCode": "*****",
                    "CountryCode": "US"
                }
            },
            "ShipTo": {
                "Address": {
                    "PostalCode": "90001",
                    "CountryCode": "US"
                }
            },
            "ShipFrom": {
                "Address": {
                    "AddressLine": "******",
                    "City": "Los Angeles",
                    "StateProvinceCode": "*****",
                    "PostalCode": "*****",
                    "CountryCode": "US"
                }
            },
            "Service": {
                "Code": "03"
            },
            "TaxInformationIndicator": "True",
            "NumOfPieces": "1",
            "Package": [
                {
                    "PackagingType": {
                        "Code": "02"
                    },
                    "PackageWeight": {
                        "Weight": "7.31",
                        "UnitOfMeasurement": {
                            "Code": "LBS"
                        }
                    }
                }
            ],
            "ShipmentRatingOptions": {
                "NegotiatedRatesIndicator": "True"
            }
        }
    }
}

I am targeting the URL https://onlinetools.ups.com/api/rating/v2409/Rate, but I am getting response something like:

{"response":{"errors":[{"code":"9110034","message":"Missing or invalid request option."}]}}

While the RequestOption is available in the payload. What I am doing wrong? (I have access token).

my code for call is

 $version = "v2409";
 $requestoption = "Rate";
 $accessToken = $this->getUpsAccessToken(); // Get OAuth token

    if (!$accessToken) {
        return ['error' => 'Failed to get access token'];
    }
$query = array();

$curl = curl_init();

$payload = $this->processPackageRateRequest($ShippingConstants, $PostalCode, $CountryCode, $BoxCount, $ShippingWeight, $ServiceType, $addressType);

//print_r(json_encode($payload));


curl_setopt_array($curl, [
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer $accessToken",
    "Content-Type: application/json",
    "transId: string",
    "transactionSrc: testing",
    "Accept: application/json",
    
  ],
  CURLOPT_POSTFIELDS => json_encode($payload),
  CURLOPT_URL => "https://onlinetools.ups.com/api/rating/" . $version . "/" . $requestoption . "?" . http_build_query($query),
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_CUSTOMREQUEST => "POST",
]);

$response = curl_exec($curl);
$error = curl_error($curl);

curl_close($curl);

if ($error) {
  echo "cURL Error #:" . $error;
} else {
  echo $response;
}

the function "processPackageRateRequest" returns the payload in formatted version.

Update based on the comment

You are setting a random string value to the additionalinfo parameter. The only valid value listed in the API docs is timeintransit. So either remove additionalinfo parameter or set it's value to timeintransit.

Original Answer

You have one required field missing in your data. For UnitOfMeasurement you need to provide both Code and Description. Check this.

So add relevant text description to your data.

                    ...
                    "PackageWeight": {
                        "Weight": "7.31",
                        "UnitOfMeasurement": {
                            "Code": "LBS",
                            // Set the relevant description here
                            "Description": "Pounds"
                        }
                    }
                    ...