Getting error of "\"UpdateReservationRQ: NGHP.ERR.0363: Invalid number of rooms. (Code: 1)" while booking multiple rooms under 1 PNR

Question

This is the payload i'm sending to sabre create-passenger-name-record api for booking muitple rooms under single pnr.

Its just the hotelBook schema payload can someone let me know what i'm doing wrong.

{

"HotelBook": {
    "BookingInfo": {
        "BookingKey": "lp6iuxh0pm"
    },
    "Rooms": {
        "Room": [
            {
                "Guests": {
                    "Guest": [
                        {
                            "Contact": {
                                "Phone": "8778566755"
                            },
                            "FirstName": "ajay",
                            "LastName": "kumar",
                            "Index": 1,
                            "LeadGuest": true
                        }
                    ]
                },
                "RoomIndex": 1
            },
            {
                "Guests": {
                    "Guest": [
                        {
                            "Contact": {
                                "Phone": "8778566755"
                            },
                            "FirstName": "ajay",
                            "LastName": "kumar",
                            "Index": 1,
                            "LeadGuest": false
                        }
                    ]
                },
                "RoomIndex": 2
            }
        ],
        "NumberOfRooms": 2
    },
   

}

I have tried everything except the CSL method.