Flutter – type 'Null' is not a subtype of type 'List<dynamic>'

When I try to fetch data from API the follow error shows.

Error : type ‘Null’ is not a subtype of type ‘List<dynamic>’

Here I’m sharing the calling function and model. When I fetch another types API URL using this same model it works perfectly. But in this case it shows the given error. But when I create another model it works.

    FutureBuilder(
     future: movieObj.fetchMovies(movieType.cast,id: movieData.id),
     builder: (context, snapshot) {
      if (snapshot.hasData) {
        List<MovieModel>movieData = snapshot.data??[];
         return layouts(movieData: movieData);
        }
        return Center(child: CircularProgressIndicator(),);
     },
    )

Model :

// To parse this JSON data, do
//
// final MovieModel = MovieModelFromJson(jsonString);

import 'dart:convert';

MovieModel MovieModelFromJson(String str) => MovieModel.fromJson(json.decode(str));

String MovieModelToJson(MovieModel data) => json.encode(data.toJson());

class MovieModel {
    bool? adult;
    String backdropPath;
    int? id;
    String? originalLanguage;
    String? originalTitle;
    String? overview;
    double? popularity;
    String posterPath;
    String? releaseDate;
    String title;
    bool? video;
    double? voteAverage;
    int? voteCount;

    MovieModel({
        required this.adult,
        required this.backdropPath,
        required this.id,
        required this.originalLanguage,
        required this.originalTitle,
        required this.overview,
        required this.popularity,
        required this.posterPath,
        required this.releaseDate,
        required this.title,
        required this.video,
        required this.voteAverage,
        required this.voteCount,
    });

    factory MovieModel.fromJson(Map<String, dynamic> json) => MovieModel(
        adult: json["adult"],
        backdropPath: json["backdrop_path"],
  
        id: json["id"],
        originalLanguage: json["original_language"],
        originalTitle: json["original_title"],
        overview: json["overview"],
        popularity: json["popularity"]?.toDouble(),
        posterPath: json["poster_path"],
        releaseDate: json["release_date"],
        title: json["title"],
        video: json["video"],
        voteAverage: json["vote_average"]?.toDouble(),
        voteCount: json["vote_count"],
    );

    Map<String, dynamic> toJson() => {
        "adult": adult,
        "backdrop_path": backdropPath,
        "id": id,
        "original_language": originalLanguage,
        "original_title": originalTitle,
        "overview": overview,
        "popularity": popularity,
        "poster_path": posterPath,
        "release_date": releaseDate,
        "title": title,
        "video": video,
        "vote_average": voteAverage,
        "vote_count": voteCount,
    };
}

Response :

import 'dart:convert';
import 'package:http/http.dart';
import 'package:movie_application/api%20Integration/model/movieModel.dart';
import 'package:movie_application/api%20Integration/model/similarModel.dart';
import 'package:movie_application/constants/apiConstants.dart';

enum movieType {
  nowPlaying,
  popular,
  topRated,
  upComing,
  similar,
  latest,
  videos,
  cast
}

class movieClass {
  Future<List<MovieModel>?> fetchMovies(movieType type, {id}) async {
    var url = '';
    if (type == movieType.nowPlaying) {
      url = movieUrl + CnowPlaying;
    } else if (type == movieType.popular) {
      url = movieUrl + Cpopular;
    } else if (type == movieType.topRated) {
      url = movieUrl + CtopRated;
    } else if (type == movieType.upComing) {
      url = movieUrl + CupComing;
    } else if (type == movieType.cast) {
      url = movieUrl + id.toString() + Ccast;
    } else if (type == movieType.similar) {
      url = movieUrl + id.toString() + Csimilar;
    } else if (type == movieType.videos) {
      url = movieUrl + id.toString() + Cvideos;
    }
    Response response = await get(Uri.parse(url + '?api_key=3c63914fd23ecbed6507f4396ed68164'));
    Map<String,dynamic>jsonBody = jsonDecode(response.body);
    List<dynamic>result = jsonBody['results'];
    List<MovieModel>resultList = result.map((e) => MovieModel.fromJson(e)).toList();
    print(url);
    return resultList;
  }

}