sudo su # login as root
cd /var/lib/apt/lists/
rm -fr *
cd /etc/apt/sources.list.d/
rm -fr *
cd /etc/apt
cp sources.list sources.list.old
cp sources.list sources.list.tmp
sed 's/ubuntuarchive.hnsdc.com/us.archive.ubuntu.com/' sources.list.tmp | tee sources.list
rm sources.list.tmp*
apt-get clean
apt update