The Auto-detect feature simply opens a web page and checks for some text it expects to see there.
From your screenshot I can see that you've changed the web page it opens, so it's probably the case that it's not finding the text you've told it to expect.
But the main thing is this -- the auto detect adapter is not a feature you need! Once you have correctly set the adapter and can see packets being scanned -- just turn off auto-adapter detection and don't worry about it anymore.
Now as for playing a video on youtube and not seeing good results, this could be for any number of reasons.. In the modern day there are lots of streams that have no simple streaming media links that url snooper can detect, and https encrypted traffic can hide streaming media urls.