Youtube / youtube channels add-ons nut running (no access)

Hi friends,
I am new at osmc / kodi and have osmc vers. 19.3 matrix running well on my Mac. This is including youtube, youtube channels (and spotify).
For that purpose I generated the google-API according respective hints.
So far so good.

In parallel I started osmc same way on my brandnew vero4K+.
Neither youtube (nor spotify) are connecting.
Youtube add-ons habe authentication failures on server side.
Spotify just refuses access.

There are many people with same question on the web but no answers.

Where / how can I get help​:interrobang::flushed: