我的 Centos 6 有问题。实际上，我正在尝试运行任何命令，例如yum updateoryum upgrade或yum install mysqlmysql-server。每次，我都会收到以下错误：
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=os error was
14: PYCURL ERROR 22 - "The requested URL returned error: 403"
Error: Cannot find a valid baseurl for repo: base