Thank you for pointing to that system log.
But i am not sure if this is acctually the reason for the filed to download image, since it happens more then every two hours and therefor might not be related to the [Logs] [3/5/2020, 4:00:20 PM] Failed to download image
Mar 03 20:07:25 ShortUUI balenad[1292]: time="2020-03-03T20:07:25.076395426Z" level=warning msg="failed to download layer: \"unexpected EOF\", retrying to read again"
This happens roughly every 20 minutes 
Do you know if this is a server error, should i upgrade OpenBalena or a missconfigured app?