Can not jump to next task. Mission: **FILES MASTER**. Task: **Upload a file using API**

I uploaded file “superfast.html” by my flutter app to the “mission” folder, but can not jump to next task. The file appeared in the Backendless file storage. Log from flutter:

I/flutter (21769): File has been uploaded. File URL is -

Hi, @Alexander_Denysiuk

We have assigned you this task. You may check it. Could you, please provide us an example of your code that you used to complete this mission in order to study this issue.


This mission has already been marked as completed.

My flutter code:

void _uploadFile() async {
Directory appDocDir = await getApplicationDocumentsDirectory();
String appDocPath = appDocDir.path;

String _filename = '$appDocPath/superfast.html';

File file = await File(_filename).writeAsString('Hello mbaas!\nUploading files is easy!');
Backendless.files.upload(file, '/mission').then((response) {
  print("File has been uploaded. File URL is - " + response);