Error message when trying to get a puppet class by ID

When trying to run:

curl -s -H "Accept:application/json" -k -u $USER:$PASS --get
https://$HOST/api/puppetclasses/10 <https://%24host/api/puppetclasses/10>

where 10 is the ID number of one of the puppet classes, I'm getting an
error:

{"error":{"message":"Missing template api/v1/puppetclasses/show,
api/v1/base/show, api/base/show with {:locale=>[:en], :formats=>[:json],
:handlers=>[:erb, :builder, :rabl]}. Searched in:\n *
&quot;/usr/share/foreman/app/views&quot;\n *
&quot;/opt/rh/ruby193/root/usr/share/gems/gems/apipie-rails-0.0.18/app/views&quot;\n"}}

any ideas?

Tal