I’m not sure if your device has reliable internet connection as it appears not logged in to the CMS quite often which obviously might affect the downloading process.
Regarding image error, it could be because it wasn’t downloaded correctly, if for example the connection was cut, other than that you can also have a look here - Displaying Images
In your case, it could be beneficial to make sure that this player can correctly display your default layout first before you schedule your layout with big videos, as now it will try to download all of them, again if it looses the connection during that process, it may very well cause issues.