The "HTTP Error 404 - Not Found" error  yum typically indicates that the repository or package metadata files could not be found on the server. This can happen for a variety of reasons, and here are some steps to troubleshoot and resolve the issue:

1. Verify Repository URL:

   • Ensure that the repository URL in your configuration files (usually located in /etc/yum.repos.d/) is correct and accessible from your network. Check for any typos or mistakes in the URL.

2. Update Repository Metadata:

   • Run the following commands to clean and regenerate the repository metadata:
     bash

• • sudo yum clean all sudo yum makecache

• Check Internet Connection:

  • Verify that your server has a stable and active internet connection.

• Temporary Disable Repository:

  • If the error persists with a specific repository, you may temporarily disable it by setting enabled=0 in the repository configuration file.

• Check for Proxy Settings:

  • If your server is behind a proxy, make sure that the proxy settings are correctly configured. You might need to set up proxy settings in /etc/yum.conf or in the specific repository configuration file.

• Check Firewall Rules:

  • Verify that your server's firewall is not blocking outgoing connections to the repositories. Allow traffic on the relevant ports (usually 80 and 443).

• Temporary DNS Issues:

  • It's possible that there might be temporary DNS resolution issues. Try using a different DNS server or check if your current DNS server is functioning properly.

• Check SELinux:

  • If you have SELinux enabled, it might be preventing the server from accessing certain directories or files. You can temporarily set SELinux to permissive mode:
    bash