@Mahesh Hi Mahesh, it seems you are passing wrong token, I guess you are asking for this.
{
"token": "245263",
"symbol": "NATURALGAS22OCTFUT",
"name": "NATURALGAS",
"expiry": "26OCT2022",
"strike": "0.000000",
"lotsize": "1250",
"instrumenttype": "FUTCOM",
"exch_seg": "MCX",
"tick_size": "10.000000"
}