Error 400 using Flutter/Dart

Hey guys, I’m trying to fetch the API using flutter/dart for a web App, but I got 400 error.

Future fetchData() async {

final response = await http.get(

Uri.parse("https://api.company-information.service.gov.uk/company/06500244"),

headers: {

  HttpHeaders.authorizationHeader: "Basic ${apiKey}",

},

);

final jsonResponse = convert.json.decode(response.body);

if (response.statusCode == 200) {

print(jsonResponse.toString());

} else {

throw Exception(response.statusCode);

}
}

Any other information I need to pass other than apikey?

Thanks.