PDF preview refused to connect using PHP Laravel - php

Question

I'm making some kind of form be able to upload PDF file. And I also make a label to preview the file that I'm uploading. But somehow the label wont preview the file with error massage : refused to connect. Can somebody help me with it?
image form preview
So here's the PHP code for the label on the view file that I use :
<div class="form-group row">
<label class="col-md-2 col-form-label">File</label>
<div class="col-md-6">
<input type="file" name="file" id="file" class="form-control" required>
<iframe src="{{ $data['data']['files'] }}" style="width: 1000px; height:500px;" frameborder="0" id="filePreview" class="mt-2"></iframe>
</div>
<small class="text-small">{{ $errors->first('file') }}</small>
</div>
And here is the edit and update controller that I use for that view
public function edit($id)
{
$system = new SystemService();
$systemData = $system->list_badges();
$data['system'] = $systemData['data'];
$api = new SettingService();
$data['data'] = $api->get_about($id);
$data['title'] = 'Ubah Tentang Aplikasi';
$data['default'] = $this->folder;
$data['data_view'] = $this->folder . '/edit';
return view('template', $data);
}
public function update(Request $request, $id)
{
$api = new SettingService();
if ($request->hasFile('file')) {
$file = $request->file('file');
$mime = $file->getClientOriginalExtension();
$filter_file = [
'pdf',
'doc', 'docx',
'csv', 'xls', 'xlsx',
'png', 'jpg', 'jpeg',
];
if (!in_array($mime, $filter_file)) {
return back()->with('failed', 'file extention not correct');
}
$file_path = $request->file('file')->path();
$file_name = md5(date('YmdHis') . $file->getClientOriginalName()) . '.' . $file->getClientOriginalExtension();
$data['file_path'] = $file_path;
$data['file_name'] = $file_name;
}
$result = $api->update_about($id, $data);
if (isset($result['errors'])) {
return redirect($this->folder . '/' . $id . '/edit')->withErrors($result['errors'])->withInput()->with('failed', $result['message']);
}
if ($result['status'] == false) {
return redirect($this->folder . '/' . $id . '/edit')->withInput()->with('failed', $result['message']);
}
return redirect($this->folder)->with('success', $result['message']);
}
Thankyou