Sending Attachments not work with plug-in form&email

Task: send a file attached to the mail message via the contact form
Screen_form
In the screenshot you can see that there is a field for attaching files. But I can not add the file there. There is no selection button, and if you try to drag and drop the file into this area, it is not attached.
The letter is sent without this file and the page is not shown: thank you.
I can not understand why the file is not attached

plugins/form/form.yaml
enabled: true
built_in_css: true
files:
multiple: false # To allow multiple files, default is single
limit: 10 # Number of allowed files per field (multiple required)
filesize: 5 # Maximum file size allowed (in MB)
destination: 'self@' # Where to upload the files (path and self@, page@, theme@)
avoid_overwriting: false # Prevent files with the same name to be overridden. Date prefix will be added
random_name: false # Generate a random 15 long string name for the uploaded files
accept: # List of mime/types or file extens ions allowed (ie, image/*,.zip,.mp4)

• image/*

  ---

  form.md

  YAMLCopy

  
  title: Связь
  form:
  method: GET
  name: my-nice-form
  fields:
      - name: name
        label: Имя
        placeholder:  ваше имя
        autofocus: on
        autocomplete: on
        type: text
        validate:
          required: true
  
      - name: email
        label: Е-майл
        placeholder:  ваш е-майл
        type: text
        validate:
          rule: email
          required: true
  
      - name: message
        label: Сообщение
        size: long
        placeholder: сообщение
        type: textarea
        validate:
          required: true
  
      -  name: my-file
         label: 'Добавить файл'
         type: file
  
  buttons:
      - type: submit
        value: Submit
        classes: btn
      - type: reset
        value: Reset
        classes: btn
  process:
      - email:
          from: "{{ config.plugins.email.from }}"
          to:
            - "{{ config.plugins.email.from }}"
            - "{{ form.value.email }}"
          subject: "[Feedback] {{ form.value.name|e }}"
          body: "{% include 'forms/data.html.twig' %}"
          attachments: [my-file]
      - save:
          fileprefix: feedback-
          dateformat: Ymd-His-u
          extension: txt
          body: "{% include 'forms/data.txt.twig' %}"
      - message: Thank you for your feedback!
      - display: thankyou
  ---