How to solve forbidden error when uploading files to do spaces

I am trying to upload files in my flutter application using dospace and I have been getting this error message : flutter: DOException { statusCode: 403, reasonPhrase: “Forbidden”, responseBody: “<?xml version=“1.0” encoding=“UTF-8”?><Error><Code>InvalidAccessKeyId</Code><RequestId>tx0000000000000245603d7-0063457665-5c963c72-fra1b</RequestId><HostId>5c963c72-fra1b-fra1-zg02</HostId></Error>” }

This is my flutter code

 Future<void> uploadFileMethod() async {
    dospace.Spaces spaces = dospace.Spaces(
      //change with your project's region
      region: "fra1",

      //change with your project's accessKey
      accessKey: "*************",
      //change with your project's secretKey
      secretKey: "*****************************",
      endpointUrl: 'https://fra1.digitaloceanspaces.com',
    );
    try {
      var pickedFile;
      FilePickerResult? result = await FilePicker.platform.pickFiles();

      if (result != null) {
        File file = File(result.files.single.path as String);
        pickedFile = file;
      } else {
        // User canceled the picker
        return;
      }



      String projectName = "*******"; // change to projectname
      // change with your project's region
      String region = "fra1";
      // change with your project's folder
      String folderName = "videofiles";
      String fileName = pickedFile.path.split('/').last;

      String? etag = await spaces.bucket(projectName).uploadFile(
            "$folderName/$fileName",
            pickedFile,
            "image/jpg",
            dospace.Permissions.public,
          );
      print(etag);
     

      await spaces.close();
    } catch (error) {
      print(error);
    }
  }