Create list item by restful

Code:

  function createListItem() { 
            var item =  {
                "__metadata": { "type": "SP.Data.listnameListItem" },   
                "Title": "testsetsetset",
                "Column1": "Test", 
                "Column2": "Test" , 
            } ;

        $.ajax({
              url: apphostweb + "/_api/web/lists/getbytitle('" + listname + "')/items",
            type: "POST",       
            contentType: "application/json;odata=verbose",  
           data: JSON.stringify(item),
            headers: {
                "Accept": "application/json;odata=verbose",
                "X-RequestDigest": $("#__REQUESTDIGEST").val()
            },
            success: function (data) {
                alert("Successful");            
            },
            error: function (data) {
                alert("Failure");
            }
        });

}

I can insert the title to the list, but after I added the column1 and column2 field in the request. There is a error:

{"error":{"code":"-1, Microsoft.SharePoint.Client.InvalidClientQueryException","message":{"lang":"en-US","value":"A type named 'SP.Data.listnameListItem' could not be resolved by the model. When a model is available, each type name must resolve to a valid type."}}}

Can we create whole item using this method? OR another method should be used?