I was creating label through sandbox access token ,But i am getting Issue .

Request body:

curl --request POST
--url https://api.easyship.com/2023-01/labels
--header 'accept: application/json'
--header 'authorization: Bearer sand_YvzGxHM3dJA7E+8j1NuKQr8Z8qhEhRxv04UQZlnGCTQ='
--header 'content-type: application/json'
--data '
{
"shipments": [
{
"easyship_shipment_id": "ESIN10214045"
}
]
}

Issue:

{
"error": {
"code": "invalid_content",
"details": [
"Shipments not ready to be shipped: ESIN10214045"
],
"message": "The request body content is not valid.",
"request_id": "f8f75918bb8a9567ad1bcf158a4f1a3f",
"type": "invalid_request_error"
}
}

The same question is already present in the forum https://developers.easyship.com/discuss/64871aa5cf4e4f000a977d2d.

The provided solution is ,

As we may not have much courier service in the sandbox environment, you might consider testing on the production environment and canceling the shipping label before arranging for pickup to test the whole flow for creating labels.

The shipping fee can be refunded as long as the shipment is not picked up by couriers after the shipping label is canceled.

I am a newbie to Easyship. Also recently I created an account on Easyship. I have chosen the premium plan for the trial. Can you guide me on not having the cost and creating labels like the above-mentioned kindly share the steps.