This could either be a temporary issue, in which case I’d recommend trying it again after some time, or it could mean that said mirror is currently broken as explained here: W: Failed to fetch from mirror.whonix.de
However, in your case there seems to be something quiet different going on. The URL says “essie” when in reality it should spell “jessie”. Could you please verify that this is in fact the correct spelling because otherwise you seem to have tipped us off to a rather problematic typo.
Furthermore I’ve moved the thread, since this seems to apply to files not specific to Qubes-Whonix.
Have a nice day,