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

Questions
1 
** ```
        "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!