Sky I tried to replicate with a few installs, to see if something is wrong with fosshost, all good here, so it probably is a location issue.
Just try a different mirror, best one close to you. Comment out the fosshost mirror (place a #
in front of the Server line, like:
# Server = https://mirrors.fossho.st/kaos/$repo
then place the mirror you want to use as the first uncommented mirror. To update & force a new database, it will be good to update with sudo pacman -Syyuu