[Solved] Linq OrderBy Error: Value cannot be Null Parameter Source

Hi ramco1917,

As per the error message source parameter is null. 

So check response returns items or not before applying OrderBy clause.

var client = new RestClient("www.googleapis.com/youtube/v3");
var request = new RestRequest("search", Method.GET);
request.AddParameter("part", "snippet");
request.AddParameter("type", "video");
request.AddParameter("maxResults", 50);
request.AddParameter("channelId", "UCVw");
request.AddParameter("key", "AIzaG8");

var response = client.Execute<YoutubeSearchListResponse>(request);
List<Item> orderByPublishAt = response.Data.items.ToList();
if (orderByPublishAt.Count > 0)
{
    orderByPublishAt = orderByPublishAt.OrderBy(x => x.snippet.publishedAt).ToList();
}