Sometimes, content in Programs might be loaded from external sources, like Vimeo or YouTube. Unfortunately, we don't have control over such content, and Gnowbe might be unable to force the sound to play.
Un-mute your phone
Usually, the solution is to simply check if your phone is muted (check the physical switch if you have it). If it isn't, and you are still not hearing audio, try viewing these videos on Gnowbe Web.