RSS Import

Just starting with wordpress and installed the rssimport plugin and having problems getting it to work. I’ve created a page with the following content

[RSSImport display=”5″ feedurl=”https://bueltge.de/feed/”%5D

and get this error

Error: Feed has a error or is not valid

I’ve tried multiple variations without success

I’ve tried with this url as the feed which works with the rss widget

https://news.search.yahoo.com/news/rss;_ylt=A0WTTkp11ihKNIwA7AnQtDMD;_ylu=X3oDMTA3MTBsZGZsBHNlYwNhZG0-?ei=UTF-8&c=&p=pottery&eo=UTF-8

thanks

Paul