Events sent by measurement protocol are not fully received and reported by GA

Question

I'm trying to send some events from the backend of my website to GA. I've collected client_id from the client, and I send the purchase event using the following request:

POST /mp/collect?api_secret=xxxxxxxxxxxxxxxxxxxxxxxxxx&measurement_id=G-XXXXXXXX&measurement_id=G-XXXXXXXX HTTP/1.1

{
    "client_id": "1079763317.1697693644",
    "events": [
        {
            "name": "purchase",
            "params": {
                "currency": "IRR",
                "transaction_id": "78248861",
                "value": "8792000",
                "coupon": null,
                "items": [
                    {
                        "item_name": "Item 1",
                        "price": "4396000",
                        "item_category": "ADL",
                        "quantity": 1,
                        "item_variant": "Variant 1"
                    },
                    {
                        "item_name": "Item 1",
                        "price": "4396000",
                        "item_category": "ADL",
                        "quantity": 1,
                        "item_variant": "Variant 2"
                    }
                ]
            }
        }
    ]
}

The request is being accepted successfully with the code 204. I have the log for all the requests and I'm sure that this request is being sent and accepted this way more than 7000 times daily.

But when I see the reports in GA, the count of this events are a lot less than what it should be, maybe about 800. It means that somehow a lot of these events are being missed.

Do you have any idea that what's wrong here?

Answer 1

value and price values must be a number (without quotes).

transaction_id must be unique.

item_id is required.