Hallo!

Tut mir leid, mein Deutsch is sehr schlecht so I will continue in English.

2.17 is very old and we have updated the YouTube spout since then.

If the link you copied looks like one of these:

• https://www.youtube.com/channel/<channel-id> where <channel-id> contains an hyphen
  
• https://www.youtube.com/user/<username>

you will need this change which is included in selfoss 2.18.

It the URL looks different, please share it.