Puppet server hostname does not match certificate - can't authenticate.

err: Could not retrieve catalog from remote server: Server hostname 'puppet' did not match server certificate; expected master

The agent configuration file seems to be communicating with a different server (master) name than that for which the puppet master has the certificate for. The only way to solve this is by re-generating the puppetmaster server certificate with the correct hostname as that defined in the agent configuration file.

To quickly test, another way is to change /etc/hosts file of agent and map the hostname and IP of the puppetmaster server.