Sending Attachments not work with plug-in form&email

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1

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

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
---