How do I connect to download sites after APT damage?

Question

I saw so much news from Ubuntu about snaps that I thought it was time I learnt more.

So I found the tutorial on the website :

https://tutorials.ubuntu.com/tutorial/basic-snap-usage#1

I am a retired Ubuntu end user so I tried just reading the steps first. Then tried to install snapd. 41 packages were "no longer required" as you will see from the clips of terminal messages below. I don't know why apt could not connect to the network because I was able to access other websites. Maybe the removal disabled the connection??

I am preparing to upgrade to Ubuntu 18.04.1 and am deleting lots of old files. That is why I decided to remove the "no longer required" as the messages told me. Big mistake. The removal ran for maybe an hour and then the software repositories were not accessible. "Failed to download repository information. Check your Internet connection."

Now I hope you will be able to tell me how to correct the situation!! I have much more terminal messages.

---

chas@Charles-PC:~$ sudo apt install snapd
[sudo] password for chas: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  libllvm4.0 libllvm5.0 libqmi-glib1 libqpdf17 linux-headers-4.4.0-101
  linux-headers-4.4.0-101-generic linux-headers-4.4.0-103
  linux-headers-4.4.0-103-generic linux-headers-4.4.0-104
<>
linux-headers-4.4.0-81-generic linux-headers-4.4.0-83
  linux-headers-4.4.0-83-generic linux-headers-4.4.0-87
<>
linux-headers-4.4.0-98-generic linux-image-4.4.0-101-generic
  linux-image-4.4.0-103-generic linux-image-4.4.0-104-generic
<>
linux-image-extra-4.4.0-103-generic linux-image-extra-4.4.0-104-generic
  linux-image-extra-4.4.0-109-generic linux-image-extra-4.4.0-112-generic
<>
Use 'sudo apt autoremove' to remove them.
The following packages will be upgraded:
  snapd
1 to upgrade, 0 to newly install, 0 to remove and 12 not to upgrade.
Need to get 14.1 MB of archives.
After this operation, 1,167 kB of additional disk space will be used.
Err:1 http://ubuntu.mirror.neology.co.za/ubuntu xenial-updates/main amd64 snapd amd64 2.33.1ubuntu2
  Cannot initiate the connection to ubuntu.mirror.neology.co.za:80 (2001:43e8:10:42::25). - connect (101: Network is unreachable) [IP: 2001:43e8:10:42::25 80]
E: Failed to fetch http://ubuntu.mirror.neology.co.za/ubuntu/pool/main/s/snapd/snapd_2.33.1ubuntu2_amd64.deb  Cannot initiate the connection to ubuntu.mirror.neology.co.za:80 (2001:43e8:10:42::25). - connect (101: Network is unreachable) [IP: 2001:43e8:10:42::25 80]

E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
chas@Charles-PC:~$ sudo apt autoremove