var username = "Some login name";

            var Url = "Site URL";
            using (var context = new ClientContext(Url))
            {
                var securepass = new SecureString();
                foreach (char c in password)
                {
                    securepass.AppendChar(c);
                }
                log.LogInformation("C# HTTP");
                SharePointOnlineCredentials credentials = new SharePointOnlineCredentials(username, securepass);
                context.Credentials = credentials;
                Web web = context.Web;
                context.Load(web);
                log.LogInformation("web object load");
                context.ExecuteQuery();