getting 404 not found in bulk_update_price_quantity API in Explorer for sku

[valuenature]

Hi team,

I am calling https://api.ebay.com/sell/inventory/v1/bulk_update_price_quantity in API Explorer and filled application token and my request is like JSON below , but it says SKU not found? I am sure that SKU exists. 

Any help is greatly appreciated.

{
"requests": [
{
"offers": [
{
"availableQuantity": 2,
"offerId": "string",
"price": {
"currency": "AUD",
"value": 56
}
}
],
"shipToLocationAvailability": {
"availabilityDistributions": [
{
"fulfillmentTime": {
"unit": "BUSINESS_DAY",
"value": 2
},
"merchantLocationKey": "Australia",
"quantity": "3000"
}
],
"quantity": 2
},
"sku": "PLAY-MAST-BU"
}
]
}