Initial installation of Satellite 6.7 under hypervisor Virtualbox fails

Issue

• Why does the installation of satellite 6.7 fail during 'satellite-installer' step, under hypervisor: Virtualbox 6.1.6?
• Upgrading a Satellite 6.6 system to 6.7 also fails.

# ./satellite-installer --scenario satellite --foreman-initial-organization ORGNAME --foreman-initial-location LOCATIONNAME --foreman-initial-admin-username admin --foreman-initial-admin-password SOMEPASSWORD
Package versions are locked. Continuing with unlock.
 /Stage[main]/Foreman_proxy::Register/Foreman_smartproxy[sat6.local]: Could not evaluate: Proxy sat6.local cannot be retrieved: unknown error (response 500)
/usr/share/foreman-installer/modules/foreman/lib/puppet/provider/foreman_smartproxy/rest_v3.rb:7:in `proxy'
/usr/share/foreman-installer/modules/foreman/lib/puppet/provider/foreman_smartproxy/rest_v3.rb:13:in `id'
/usr/share/foreman-installer/modules/foreman/lib/puppet/provider/foreman_smartproxy/rest_v3.rb:17:in `exists?'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/property/ensure.rb: