mjhjmtu

Synaptic package manager is freezing when it attempts to download packages for installation.

I have tried to install using terminal, but I keep receiving a message saying: 'connection failed'
'unable to fetch some archives, maybe run apt-get update or try with --fix-missing?'

My internet connection is fine, what has gone wrong?

I'm only used to debian and apt, but I guess it must be the same.

When you try apt-get update it shows which server(s) it try to connect to.
Are those servers reachable?
Is apt set up to use a proxyserver which is not running?

These settings are under /etc/apt, for instance /etc/apt/sources.list or /etc/apt/apt.conf.d

Update:
ign: means apt for some reason ignores the repository.

Try

cd /var/lib/apt
mv lists lists.old
mkdir lists
apt-get update


Try
set | grep -i proxy
grep -sir proxy /etc/apt

If it lists any proxy, is it responsive?

Update:
So the the settings say there is supposed to run a HTTP_PROXY on port 4001

Either start it, if you know what it is, or remove the references to it.
It could be set in your ~/.profile, /etc/profile or ~/.bashrc
Or in your network settings.

For now, do a unset HTTP_PROXY and the other proxy-related keywords.

See also https://askubuntu.com/questions/1030454/removing-proxy-for-apt