Flutter API Call

Question

I used flutter to make small application that uses API, when I run the application on mobile it works fine, however when I run it on Chrome (web), it gives an host debug. The API is a sinch API that it is used to send a message.

Please help me know why an APIs may give exception on web. The exception is:

Error: XMLHttpRequest error.
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 299:10 createErrorWithStack
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/core_patch.dart 355:28 _throw
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/core/errors.dart 120:5 throwWithStackTrace C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/zone.dart 1385:11 callback C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/schedule_microtask.dart 40:11 _microtaskLoop C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/schedule_microtask.dart 49:5 _startMicrotaskLoop C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 166:15

//Send the request

    Uri uri =Uri.parse($sinchAPI);

    final response = await http.post(uri,
        headers: <String, String>{
          "Content-Type": "application/json",
          "Authorization": "Bearer $apiToken",                            },
        body: jsonEncode(<String, dynamic>{
          "from": from,
          "to": phoneNumbersList,
          "body": messageController.text,
          "type": "mt_text",
          "feedback_enabled":"true",
        }));