Check for Updates (ElementaryOS 6.1)

Question

I can't update software

This is error messsage

E: http://mirrors.ubuntu.com/mirrors.txt Mirrorlist is not (yet) available (Could not connect to mirrors.ubuntu.com:80 (91.189.89.32), connection timed out) 
E: The repository 'mirror://mirrors.ubuntu.com/mirrors.txt focal Release' no longer has a Release file. W: Updating from such a repository can't be done securely, and is therefore disabled by default. W: See apt-secure(8) manpage for repository creation and user configuration details. 
E: mirror://mirrors.ubuntu.com/mirrors.txt focal Release is not (yet) available (Downloading mirror file failed) 
E: The repository 'mirror://mirrors.ubuntu.com/mirrors.txt focal-updates Release' no longer has a Release file. W: Updating from such a repository can't be done securely, and is therefore disabled by default. W: See apt-secure(8) manpage for repository creation and user configuration details. 
E: mirror://mirrors.ubuntu.com/mirrors.txt focal-updates Release is not (yet) available

Answer 1

Strange but seems to happen. Have a look:

https://itectec.com/ubuntu/ubuntu-making-mirror-mirrors-ubuntu-com-highly-available/

Or more directly see if you replace the path with a file from this list matching your country: http://mirrors.ubuntu.com/

Answer 2

Use the following command to see all the PPAs added in your system:

ls /etc/apt/sources.list.d

Look for PPA here and then remove the .list file associated with PPA using the following command:

sudo rm -i /etc/apt/sources.list.d/PPA_Name_list

then, add repository

sudo pico /etc/apt/sources.list

update repository

sudo apt update

Answer 3

I had the same issue and I solved using the tip from an Ubuntu topic. It looks like it is related to some environment variables needed to the update operation with the sudo user.

Basically it suggests to use -E with sudo to pass on those environment variables to the elevated user:

sudo -E apt-get update

I did it once on terminal and AppCenter came back to work.