Get Channel Message with access_token error: 401: Unauthorized

Question

I want to get message from other' channel with oauth2 (I'm a member of that guild).

Oauth2 scope: "messages.read"

Future<ResponseApi> getChannelMessages({required String channelId, String? lastMessageId}) async {
final uri = Uri.https(
  'discord.com',
  '/api/channels/$channelId/messages',
  // {if (lastMessageId != null) 'after': lastMessageId},
);
return await http.get(
  uri,
  headers: {
    // 'Authorization': 'Bot $discordBotToken',
    'Authorization': 'Bearer ${authDiscord.accessToken}',
  },
).then((res) {
  if (res.statusCode == 200) {
    return ResponseApi(success: true, response: res);
  } else {
    throw (res);
  }
}).catchError((error, stackTrace) => ResponseApi(success: false, response: error));
}

Response: "message": "401: Unauthorized"

I tried with bot token, but it only work with channel bot is member, otherwise:

return 403: "message": "Missing Access", "code": 50001

What did I do wrong?