Patch method not working

Epicor ERP 10
1

I am trying to update customer data. I have been able to update a customer record using swagger, but I am not able to update using either Postman or Visual Studio.

In Postman, I have this URL
https://…/api/v1/Erp.BO.CustomerSvc/Customers(ARM,2004)

        {
            "Customer_SyncToCRM_c": true,
            "Customer_CRMAccountID_c": "A6UJ9A0030GI"
	}

response:
{
    "odata.error": {
        "code": "",
        "message": {
            "lang": "en-US",
            "value": "The request is invalid."
        },
        "innererror": {
            "message": "patch : An error has occurred.\r\n",
            "type": "",
            "stacktrace": ""
        }
    }
}

In Visual Studio, I tried this

var client = new RestClient("https://../api/v1/Erp.BO.CustomerSvc/Customers(ARM,2004)");
			var request = new RestRequest(Method.PATCH);
			request.AddHeader("Postman-Token", "f1b8c..");
			request.AddHeader("cache-control", "no-cache");
			request.AddHeader("Authorization", "Basic dHB..");

			var iJsonData = new
			{
				Company = "ARM",
				CustNum = 2004,
				CRMAccountID_c = "A6UJ9A002SSQ"
			};

			request.AddObject(iJsonData, "Company", "CustNum", "CRMAccountID_c");
			IRestResponse response = client.Execute(request);

			JSONResponse = response.Content;
			StatusBox.Text = JSONResponse;

The response:
{
  "odata.error":{
    "code":"","message":{
      "lang":"en-US","value":"The request is invalid."
    },"innererror":{
      "message":"patch : An error has occurred.\r\n","type":"","stacktrace":""
    }
  }
}