This error message is Could not resolve host: mirrorlist.centos.org; Name or service not known
If you encounter an error like in the picture, you may have a connectivity issue somewhere.
Check if the server has internet . Check Ip address and correct route.
Check what are the resolver and ping them
You should have line with nameserver and an IP address. Check that IP is answering. Then do an nslookup
And check this time. If it still doesn't work write ip to host information in your /etc/hosts file
Peace out !