How can I resolve a 'http error 403 - forbidden' when updating CentOS packages?

Several solutions can address this. First, verify your internet connection. Second, try switching to a different CentOS mirror using the `mirrorlist` configuration file (usually located in `/etc/yum.repos.d/`). You can find a list of mirrors at [https://www.centos.org/download/mirrors/](https://www.centos.org/download/mirrors/). Third, ensure your firewall isn't blocking access to the CentOS repositories. Finally, temporarily disable any proxies if you're using them.