Ocdownload asks for "true video url" when try to get youtube Video with youtube-dl

ocdownload asks for “true video url” when try to get youtube Video with youtube-dl, no download starts.

nc ist the newest snap and youtube-dl is the newest snap too.
curl is installed in the system. I switched to curl and set the path to the snapd version of youtube-dl.
(/var/lib/snapd/snap/bin/youtube-dl)

anything else to take care about?