Added existing Linux agent but not showing

Problem: I’ve added an existing host, accepted the certificate on the foreman server however doesn’t show host but shows the cert in Puppet CA

Expected outcome: Existing host to show in Foreman

Foreman and Proxy versions: 2.1

Foreman and Proxy plugin versions: N/A

Distribution and version: Puppet version 5.5.21, Ubuntu 18.04.4 LTS

Other relevant data:
Amended the /etc/puppetlabs/puppet/puppet.conf file to pick up the foreman server