Adding attributes to subject to validate signers

Is there anyone familiar with implementing validation on the sign requests by means of adding attributes to the subject?

Our request results in a 500 error:

{
“tasks”: [
{
“id”: “task1”,
“daysToLive” : 7,
“documents”: [
{
“action”: “SIGN”,
“description”: “Letter of intent.pdf”,
“documentRef”: “{{documentID}}”,
“id”: “doc1”,
“source”: “SESSION”
}
],
“signatureMethods”: [
{
“handwritten”: true,
“name”: “idin-sign”,
“type”: “AUTHENTICATION_BASED”
}
],
“subject” :
{
“id” : “task1Subject1”,
“attributes” :[
{
“name” : “Gender”,
“value” : “1”,
“methods”:[
“idin-sign”
]
}

                ]
       
            }
         
    }      

],
"packagingTasks": [
    {
        "id": "packagingTask1",
        "sendToArchive": false,
        "method": "pades",
        "notifications": [
            {
                "id": "packagingNotification1",
                "recipient": "test@test.nl",
                "sender": "noreply@signicat.com",
                "header": "Signicat - pades generated successfully [Benelux]",
                "message": "Dear,\n\nThe pades has been generated successfully\n\nRegards,\nSignicat",
                "type": "EMAIL",
                "schedule": [
                    {
                        "triggerStatus": "COMPLETED"
                    }
                ]
            }
        ],
        "documents": [
            {
                "taskId": "task1",
                "documentIds": [
                    "doc1"
                ]
            }                      
        ]
    }
]

}