404 errors during yum install are usually encountered when the downloaded yum metadata in your CentOS gets obsolete.
I’ll be assuming that you already have root privileges in your machine.
You have 2 options to resolve this problem.
1st option is to clear the yum metadata using this command:
[root@server ~]$ yum clean metadata [root@server ~]$
2nd option is to clear the whole yum cache using this command
[root@server ~]$ yum clean all [root@server ~]$