My Integration - DLNA-Sync | Config flow could not be loaded: 500 Internal Server Error Server got itself in trouble error when installing component

Configuration
1

Dear somebody,

I need some help. Wrote a component to synchronize play over multiple DLNA renderers.

When I attempt via install HACS I get a “Config flow could not be loaded: 500 Internal Server Error Server got itself in trouble” error.

I tried setting external URL in HA system but makes no difference. Tried solving this well into the morning hours.
Maybe I am missing something.

Any ideas?

Link to the component

2

Some files are missing, a strings.json file and the corresponding translation file en.json.
See here for examples: waqi-test/custom_components/waqi-test at main · bouwew/waqi-test · GitHub

These files are needed for showing the Config Flow user-form in the HA frontend.