Can't run software updater without error

[Aravisian]

In Software & Updates app, under "Download from", set to Main Server.
Once done, try in terminal:

sudo apt update && sudo apt full-upgrade

EDIT: Crosslinking to your other thread, as both touch on the Main Server question:

Can't Install VLC software: Ubuntu server error

Your output shows that you are using a local Regional server in Columbia, not the Main Server. The Main Server supplies to the regional locations; the onus is on them to ensure that their servers are updated and running. Sadly... many mirrors are a bit lax. For this reason, we suggest users having issues with regional mirrors to stay on Main Server. What you can do to Make Certain you are on the Main Server is elevate to root as @Forpli explains here: Once elevated to Root, select "Other lo…