Just an example I just tried: http://developer.echonest.com/api/v4/playlist/static?adventurousness=1&distribution=focused&results=10&seed_catalog=XXX&song_selection=song_hotttnesss-top&type=catalog-radio&variety=1&api_key=XXX
Earlier I was consistently getting the error, now I get the error sometimes, get a result sometimes. But I'm also trying ones with metrics in them too, like max_danceability=0.5, etc. Thank you.