Edit the Yum configfile.
# vim /etc/yum.conf
add the following line to the config:
http_caching=none
Then save the file and run the update command again.
# yum update
The update will work again.
After the update check if the centos server needs a restart.
# needs-restarting
or
# needs-restarting -r
When you have a message about the kernel you need to reboot the server.
After the update and reboot your server uses the new kernel installed.