Hey @Adi, On your puppet master execute this command which lists down all the certificates
sudo /opt/puppetlabs/bin/puppet cert list
You'll see one certificate from your agent node, execute this to sign it
sudo /opt/puppetlabs/bin/puppet cert sign certi-name
You can view all the signed certificated using this command:
sudo /opt/puppetlabs/bin/puppet cert list --all