Document converter shows busy indicator, but doesn't add content at all

<%- if @topic_view.topic.tags.present? %>
<%= t 'js.tagging.tags' %>: <%- @topic_view.topic.tags.each do |t| %> <%= t %> <%- end %>
<% end %>
** ```
        "php": ">=7.1.0",
        "silverstripe/recipe-plugin": "^1.2",
        "silverstripe/recipe-cms": "4.5.2@stable",
        "silverstripe-themes/simple": "~3.2.0",
        "silverstripe/documentconverter": "^2.0",
        "silverstripe/asset-admin": "^1.5"
```** 

Question:

I installed the document converter without cwp. It shows up, i can upload docx files, but when i click on “upload” (save) and the busy indicator showed up, there’s no changed content at all. What do i do wrong?

I’m also not sure about the ENV Variables which i have to add. (I’m trying to use it without cwp.)

DOCVERT_USERNAME = "admin"
DOCVERT_PASSWORD = "password"
DOCVERT_URL = "http://localhost:8081/testp/"

Thanks in advance!