Option Order Preview: Error 100

[DrBigData]

Get the following error when we try to make an option order on the api (preview and actual orders) :
{"Error":{"code":100,"message":"The requested service is not currently available, please try after sometime."}

Here is the payload we send for preview orders:
preview_payload = {
"PreviewOrderRequest": {
"orderType": "OPTN",
"clientOrderId": client_order_id,
"Order": [{
"allOrNone": False,
"priceType": price_type,
"limitPrice": limit_price,
"stopPrice": stop_price,
"orderTerm": order_term,
"marketSession": market_session,
"Instrument": [{
"Product": {
"symbol": symbol,
"securityType": "OPTN",
"callPut": call_put,
"expiryYear": expiry_year,
"expiryMonth": expiry_month,
"expiryDay": expiry_day,
"strikePrice": strike_price
},
"orderAction": action,
"orderedQuantity": quantity,
"quantity": quantity
}]
}]
}
}

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https://apisb.etrade.com/v1/accounts/{ACCOUNT_ID}/orders/preview