Rclone is not able to handle when the receiver -> (WebGUI) cancels the request by operations like refreshing. Thus, the error connection broke. Let's see what we can do about that. Maybe continue from where the download was cancelled. 
About the movie player, we already have that, but sadly no subtitles support yet. Maybe add it as a feature request?. There are two things you need to do to see it.
In the remote explorer:
- More -> View Type -> Grid.
- More -> Tick the load images checkbox.
Check the image for details:
