I'm trying to push json data to the webservice;

Here is my sample data;

```
    {
       "data" : {
       "username" : "demo",
       "password" : "demo1082*098/*42a", 
       "LoginToken" :     "AAFF540EC55DASEFBE7E3D8404AED31F6DD30CA2BFCE2433B9475E696GG38730"
       }
    }

```

Here is my webservice;

```
public string Post([FromBody]string data)
List<Login> datas = JsonConvert.DeserializeObject<List<Login>>(data);

```

Error; An exception of type 'System.ArgumentNullException' occurred in Newtonsoft.Json.dll but was not handled in user code

Data appears as NULL

I'm using WebAPI, restful api, C#, visual std 2015

Thanks in Advance.

EDIT;

I'm using DHC chrome extention to POST data.
HEADER;
Content-Type: application/json
BODY;

```
{
           "data" : {
           "username" : "demo",
           "password" : "demo1082*098/*42a", 
           "LoginToken" :     "AAFF540EC55DASEFBE7E3D8404AED31F6DD30CA2BFCE2433B9475E696GG38730"
           }
        }

```

Error;

500 Internal Server Error

EDIT;
I fount the error which is beacause of "string" kind of data. I solved the problem when I change it as "dynamic". Can someone recommend me a keyword instead of dynamic ?