I am able to create new business manager using graph api exploror by using below api

POST https://graph.facebook.com/v20.0/{user-id}/businesses {"name":"","vertical":""}

I am trying to do same by using system-user-access-token which has business_management permission still i always end-up with An unknown error has occurred

{
    "error": {
        "message": "An unknown error has occurred.",
        "type": "OAuthException",
        "code": 1,
        "fbtrace_id": "AJLLEHScJ2XZs2Zfc6LSiOP"
    }
}

Is there any way to create business manager using system-user access-token