Thanks for your reply.
I read the update problem is fixed in 11.5, so I changed the settings to Early adopter release.
I followed the CloudLinux doc: http://docs.cloudlinux.com/index.html?converting_existing_servers.html
The server is upgraded to cloudlinux from Centos.
When I try to update I get the following error:
Installation started in background
Getting bootstrapper packages to installation list:
skip package 'pp11.0.9-bootstrapper-11.0.9-rhel6.build110120608.16.x86_64' from component base -...