The black bar above the player controls should show visual ads and they appear every so often. The only way to get rid of this is by going Premium. 🙂
I don't know why it remains mostly blank for you. Perhaps something in the hosts file, or perhaps you're using an adblocker of a kind. But there is no way to get that black bar to go away other than subscribing to a paid plan.
Hope this helps, have a nice day!
Help others find this answer and click "Accept as Solution".
If you appreciate my answer, maybe give me a Like.