Had the same problem last week, just before we had to go live with the project. Layout worked fine, until I added a couple of videos. Logs and teminal showed the same error as seen above, as well as ‘[HTTP] Connection Timed Out’. Removed the videos and the errors went away.
Toubleshooted the problem for a while. Manually adding the affected files in the Linux player cache resolved it too. But not a permanent solution.
Had to do the project without the videos that caused the connection refused errors.
