Can't render custom UI

hello Kirill,

I am back from holiday and very happy to see you were able to solve your issue.
For completeness of this thread, I am adding the solution here. Please feel free to add anything else to consider necessary.

The issue was solved by adding the location configuration for css and js files of the custom UI:

  location: {
    ui: '//domain.tld/path/to/bitmovinplayer-ui.js',
    ui_css: 'styles/bitmovinplayer-ui.css',
  },

we are confirming with our engineering team wether this configuration should become mandatory and the documentation on our GH repo should be updated.

thanks

-Thomas