Track an Event issue | An account ID must be provided

Hello Community!

I’m trying to use the “Track event” endpoint, but I’m getting the error

{
     "success": 0,
     "message": "An account ID must be provided."
}

There is no mention in the documentation of account ID for this request.
Am I missing this information somewhere or is this an API mistake?
Can you help me deal with this?
Thanks in advance

{
    "url": "https://trackcmp.net/event",
    "method": "POST",
    "headers": {
        "Content-Type": "application/x-www-form-urlencoded"
    },
    "body": {
        "key": "1",
        "event": "Test 1",
        "actid": "1"
    }
}

Have a look at actid