How to Fix Error: Failed to Download Metadata for Repo ‘AppStream’ in CentOS 8.x

In CentOS8, you might have got the below error while updating the packages via yum/dnf.

"How to Fix Error: Failed to Download Metadata for Repo ‘AppStream’ in CentOS 8.x"

The below is the Cause of This Error:

You may well be aware that CentOS Linux 8 died a premature death, it reached the End Of Life (EOL) on December 31st, 2021, thus it no longer receives development resources from the official CentOS project.

This means that after Dec 31st, 2021, to update your CentOS installation, you are required to change the mirrors to CentOS Vault Mirror, where they will be archived permanently.

Here is the fix:

Type the below commands one by one fix the above error. It works good.

#sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*
#sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*
#dnf update

This is referred from https://www.tecmint.com/error-failed-to-download-metadata-for-repo-appstream/