I am not able to go forward from this lecture.
In order to be able to unlock next lecture, you must watch 90% of the video without forwarding and achieved 70% in the quiz.
If you have watched 90% of the lecture without fast forwarding, this may mean that during your session, your internet may have experienced issues so Teachable was not able to track progress.
Usually a browser refresh or clearing browser cache should take care of it.
I did the steps as you said, cleared the cache and refreshing the browser but unable to unlock the lecture