Just moments ago I lost connection to my wireless keyboard while watching a show via Plex. I then noticed a red speaker symbol in the upper left corner. I turned my wireless keyboard off (batteries are apparently dead) and restarted the Plex app. I then rebooted when a restart of the app did not fix the issue. I cannot find anything on what this is, here is a screen capture of it. The Plex menu (clicking) has sound, the actual shows do not now. Running the most recent version of Plex on a Mac Mini 2009 base model with 4 GB ram, if it matters.