There may be many reasons behind this error. Let's discuss one by one. Your system may not have enough RAM and to fix the error, open the Puppet server configuration file:
$ vim /etc/sysconfig/puppetserver
And reduce the amount of allocated RAM for the Puppet server (for example, I specified 512m instead of 2g):
After that set the DNS name of the puppet master in puppet.conf file.
$ vim /etc/puppetlabs/puppet/puppet.conf
dns_alt_names= private dns of master(same m/c)
Next, Update the dns name in the /etc/hosts file.
$ vim /etc/hosts
Now let’s start the Puppet server:
$ sudo systemctl start puppetserver