Hello there ...
I's like to use the video-widget for the sidebar, but every link to an youtube-URL returns errormessages.
What's the problem?
Documentation is not helpful.
the video widget is part of WordPress itself. Please ask for help in a general WordPress support forum:
English on wordpress.org: https://wordpress.org/support/forums/
German on wordpress.org: https://de.wordpress.org/support/forums/
Another German community support forum: http://forum.wpde.org
Please provide a sample link and the error message.