HTTP GET Works in postman but failed in Flutter even with generated dart code from postman

i try to call api using generated dart code from postman. the link i put on flutter and postman is same link but only postman work.

import 'package:flutter/material.dart';
import 'dart:async' show Future;
import 'dart:convert';
import 'package:http/http.dart' as http;

class DartAPI {


  Future getlist() async{
    var headers = {
  'Ocp-Apim-Subscription-Key': 'thekeyishere'
};
    var request = http.Request('GET', Uri.parse('https://linkishere.com/all?page=1'));

      request.headers.addAll(headers);

      http.StreamedResponse response = await request.send();
      if (response.statusCode == 200) {
        print(await response.stream.bytesToString());
      }
      else {
        print(response.reasonPhrase);
}
  } 
}

and the error i got is

'Failed Host To lookup:https://linkishere.com/all?page=1'

even i have internet on my physical devices.

how do i call api from flutter and get the same result as postman

Try this code, please!

import 'package:http/http.dart' as http;

Future<void> getlist() async {
  try {
    var headers = {
      'Ocp-Apim-Subscription-Key': 'thekeyishere',
    };
    var uri = Uri.parse('https://linkishere.com/all?page=1');

    var response = await http.get(uri, headers: headers);

    if (response.statusCode == 200) {
      print(response.body);
    } else {
      print(response.reasonPhrase);
    }
  } catch (e) {
    print('Error occurred: $e');
  }
}