I must confess… I am an Ubuntu noob. After installing Ubuntu everything I read told me to update and upgrade before doing anything. Needless to say I went down the wrong rabbit hole.
I started looking for secure (HTTPS) mirrors when in reality the solution was so much simpler.
There is a file ‘/etc/apt/sources.list.d’ contains the following by default:
Types: deb
URIs: Index of /ubuntu
Suites: resolute resolute-updates resolute-backports
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg
Types: deb
URIs: Index of /ubuntu
Suites: resolute-security
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg
The simple solution was to change these two lines to ‘HTTPS’
I have had no more issues updating or upgrading.