Following this manual item: https://docs.theforeman.org/master/Provisioning_Guide/index-foreman.html#creating-hosts-with-uefi-http-boot-provisioning_provisioning

I just ran the installer with:

env TMP= TMPDIR= foreman-installer \
    -v \
    --enable-foreman-plugin-dhcp-browser \
    --enable-foreman-plugin-discovery \
    --enable-foreman-plugin-remote-execution \
    --enable-foreman-proxy-plugin-discovery \
    --enable-foreman-proxy-plugin-remote-execution-ssh \
    --foreman-http-keytab=/etc/http.keytab \
    --foreman-ipa-authentication=true \
    --foreman-pam-service=foreman \
    --foreman-proxy-http true \
    --foreman-proxy-httpboot true \
    --foreman-proxy-log-level=DEBUG \
    --foreman-proxy-plugin-discovery-install-images=true \
    --foreman-proxy-puppetca=true \
    --foreman-proxy-tftp true \
    --no-enable-foreman-cli-ansible \
    --no-enable-foreman-plugin-ansible \
    --no-enable-foreman-proxy-plugin-ansible

And then trying to use UEFI-IPXE-HTTP I get this error:

# foreman-rake errors:fetch_log request_id=470d0b0b
2020-12-17T12:01:26 [I|app|470d0b0b] Started PATCH "/hosts/290" for 127.0.0.1 at 2020-12-17 12:01:26 +0100
2020-12-17T12:01:26 [I|app|470d0b0b] Processing by HostsController#update as */*
2020-12-17T12:01:26 [I|app|470d0b0b]   Parameters: {"utf8"=>"✓", "authenticity_token"=>"NtNx81dFDkpJ2TR+/lYamOdExw6/5vS1TkGlC39+5mWC8tWo9FDo+p0nMzmyeHdYkRSJVCMCAkvMD3XZzRqVQw==", "host"=>{"name"=>"ae5notebook", "hostgroup_id"=>"28", "environment_id"=>"2", "puppet_proxy_id"=>"1", "puppet_ca_proxy_id"=>"1", "realm_id"=>"1", "puppetclass_ids"=>[""], "managed"=>"true", "progress_report_id"=>"[FILTERED]", "interfaces_attributes"=>{"0"=>{"_destroy"=>"0", "mac"=>"54:05:db:a6:9b:00", "identifier"=>"eth0", "name"=>"ae5notebook", "domain_id"=>"3", "subnet_id"=>"1", "ip"=>"10.10.8.205", "ip6"=>"", "managed"=>"1", "primary"=>"1", "provision"=>"1", "execution"=>"1", "tag"=>"", "attached_to"=>"", "id"=>"298"}}, "architecture_id"=>"2", "operatingsystem_id"=>"39", "medium_id"=>"7", "ptable_id"=>"93", "pxe_loader"=>"iPXE UEFI HTTP", "disk"=>"", "is_owned_by"=>"5-Users", "enabled"=>"1", "model_id"=>"", "comment"=>"54:05:db:a6:9b:01", "overwrite"=>"false"}, "id"=>"290"}
2020-12-17T12:01:26 [W|app|470d0b0b] ERF42-7843 [Foreman::Exception]: HTTP UEFI boot requires proxy with httpboot feature
2020-12-17T12:01:26 [I|app|470d0b0b] Backtrace for 'ERF42-7843 [Foreman::Exception]: HTTP UEFI boot requires proxy with httpboot feature' error (Foreman::Exception): ERF42-7843 [Foreman::Exception]: HTTP UEFI boot requires proxy with httpboot feature
 470d0b0b | /usr/share/foreman/app/models/operatingsystem.rb:258:in `boot_filename'
 470d0b0b | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:134:in `dhcp_attrs'
 470d0b0b | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:110:in `build_dhcp_record'
 470d0b0b | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:30:in `block in dhcp_records'
 470d0b0b | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:29:in `map'
 470d0b0b | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:29:in `dhcp_records'
 470d0b0b | /usr/share/foreman/app/models/concerns/orchestration/dhcp.rb:214:in `dhcp_conflict_detected?'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:428:in `block in make_lambda'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:238:in `block in halting_and_conditional'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:517:in `block in invoke_after'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:517:in `each'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:517:in `invoke_after'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:136:in `run_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:825:in `_run_validation_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activemodel-6.0.3.1/lib/active_model/validations/callbacks.rb:117:in `run_validations!'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activemodel-6.0.3.1/lib/active_model/validations.rb:337:in `valid?'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/validations.rb:68:in `valid?'
 470d0b0b | /usr/share/foreman/app/models/concerns/orchestration.rb:86:in `valid?'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/autosave_association.rb:327:in `association_valid?'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/autosave_association.rb:314:in `block in validate_collection_association'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/autosave_association.rb:314:in `each'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/autosave_association.rb:314:in `each_with_index'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/autosave_association.rb:314:in `validate_collection_association'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/autosave_association.rb:219:in `block in define_autosave_validation_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/autosave_association.rb:158:in `instance_eval'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/autosave_association.rb:158:in `block in define_non_cyclic_method'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:428:in `block in make_lambda'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:200:in `block (2 levels) in halting'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:605:in `block (2 levels) in default_terminator'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:604:in `catch'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:604:in `block in default_terminator'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:201:in `block in halting'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:513:in `block in invoke_before'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:513:in `each'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:513:in `invoke_before'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:134:in `run_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:825:in `_run_validate_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activemodel-6.0.3.1/lib/active_model/validations.rb:406:in `run_validations!'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activemodel-6.0.3.1/lib/active_model/validations/callbacks.rb:117:in `block in run_validations!'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:135:in `run_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:825:in `_run_validation_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activemodel-6.0.3.1/lib/active_model/validations/callbacks.rb:117:in `run_validations!'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activemodel-6.0.3.1/lib/active_model/validations.rb:337:in `valid?'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/validations.rb:68:in `valid?'
 470d0b0b | /usr/share/foreman/app/models/concerns/orchestration.rb:86:in `valid?'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/validations.rb:84:in `perform_validations'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/validations.rb:47:in `save'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/transactions.rb:314:in `block in save'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/transactions.rb:375:in `block in with_transaction_returning_status'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/connection_adapters/abstract/database_statements.rb:278:in `transaction'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/transactions.rb:212:in `transaction'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/transactions.rb:366:in `with_transaction_returning_status'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/transactions.rb:314:in `save'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/suppressor.rb:44:in `save'
 470d0b0b | /usr/share/foreman/app/models/concerns/foreman/sti.rb:26:in `save'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/persistence.rb:621:in `block in update'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/transactions.rb:375:in `block in with_transaction_returning_status'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/connection_adapters/abstract/database_statements.rb:280:in `block in transaction'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/connection_adapters/abstract/transaction.rb:280:in `block in within_new_transaction'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/concurrency/load_interlock_aware_monitor.rb:26:in `block (2 levels) in synchronize'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/concurrency/load_interlock_aware_monitor.rb:25:in `handle_interrupt'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/concurrency/load_interlock_aware_monitor.rb:25:in `block in synchronize'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/concurrency/load_interlock_aware_monitor.rb:21:in `handle_interrupt'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/concurrency/load_interlock_aware_monitor.rb:21:in `synchronize'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/connection_adapters/abstract/transaction.rb:278:in `within_new_transaction'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/connection_adapters/abstract/database_statements.rb:280:in `transaction'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/transactions.rb:212:in `transaction'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/transactions.rb:366:in `with_transaction_returning_status'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/persistence.rb:619:in `update'
 470d0b0b | /usr/share/foreman/app/controllers/hosts_controller.rb:116:in `block in update'
 470d0b0b | /usr/share/foreman/app/models/taxonomy.rb:76:in `block in no_taxonomy_scope'
 470d0b0b | /usr/share/foreman/app/models/taxonomy.rb:83:in `block (2 levels) in as_taxonomy'
 470d0b0b | /usr/share/foreman/app/models/concerns/foreman/thread_session.rb:195:in `as_location'
 470d0b0b | /usr/share/foreman/app/models/taxonomy.rb:82:in `block in as_taxonomy'
 470d0b0b | /usr/share/foreman/app/models/concerns/foreman/thread_session.rb:154:in `as_org'
 470d0b0b | /usr/share/foreman/app/models/taxonomy.rb:81:in `as_taxonomy'
 470d0b0b | /usr/share/foreman/app/models/taxonomy.rb:75:in `no_taxonomy_scope'
 470d0b0b | /usr/share/foreman/app/controllers/hosts_controller.rb:113:in `update'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/abstract_controller/base.rb:195:in `process_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_controller/metal/rendering.rb:30:in `process_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/abstract_controller/callbacks.rb:42:in `block in process_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:112:in `block in run_callbacks'
 470d0b0b | /usr/share/foreman/app/controllers/concerns/foreman/controller/timezone.rb:10:in `set_timezone'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:121:in `block in run_callbacks'
 470d0b0b | /usr/share/foreman/app/models/concerns/foreman/thread_session.rb:32:in `clear_thread'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:121:in `block in run_callbacks'
 470d0b0b | /usr/share/foreman/app/controllers/concerns/foreman/controller/topbar_sweeper.rb:12:in `set_topbar_sweeper_controller'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:121:in `block in run_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/audited-4.9.0/lib/audited/sweeper.rb:14:in `around'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:121:in `block in run_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/audited-4.9.0/lib/audited/sweeper.rb:14:in `around'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:121:in `block in run_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:139:in `run_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/abstract_controller/callbacks.rb:41:in `process_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_controller/metal/rescue.rb:22:in `process_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_controller/metal/instrumentation.rb:33:in `block in process_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/notifications.rb:180:in `block in instrument'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/notifications/instrumenter.rb:24:in `instrument'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/notifications.rb:180:in `instrument'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_controller/metal/instrumentation.rb:32:in `process_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activerecord-6.0.3.1/lib/active_record/railties/controller_runtime.rb:27:in `process_action'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/abstract_controller/base.rb:136:in `process'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionview-6.0.3.1/lib/action_view/rendering.rb:39:in `process'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_controller/metal.rb:190:in `dispatch'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_controller/metal.rb:254:in `dispatch'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/routing/route_set.rb:50:in `dispatch'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/routing/route_set.rb:33:in `serve'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/journey/router.rb:49:in `block in serve'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/journey/router.rb:32:in `each'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/journey/router.rb:32:in `serve'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/routing/route_set.rb:834:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/apipie-dsl-2.2.9/lib/apipie_dsl/static_dispatcher.rb:67:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/apipie-rails-0.5.17/lib/apipie/static_dispatcher.rb:66:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/apipie-rails-0.5.17/lib/apipie/extractor/recorder.rb:137:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/static.rb:126:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/static.rb:126:in `call'
 470d0b0b | /usr/share/foreman/lib/foreman/middleware/telemetry.rb:10:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/apipie-rails-0.5.17/lib/apipie/middleware/checksum_in_headers.rb:27:in `call'
 470d0b0b | /usr/share/foreman/lib/foreman/middleware/catch_json_parse_errors.rb:9:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/tempfile_reaper.rb:15:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/etag.rb:27:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/conditional_get.rb:40:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/head.rb:12:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/http/content_security_policy.rb:18:in `call'
 470d0b0b | /usr/share/foreman/lib/foreman/middleware/logging_context_session.rb:22:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/session/abstract/id.rb:266:in `context'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/session/abstract/id.rb:260:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/cookies.rb:648:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/callbacks.rb:27:in `block in call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/callbacks.rb:101:in `run_callbacks'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/callbacks.rb:26:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/actionable_exceptions.rb:17:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/debug_exceptions.rb:32:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/railties-6.0.3.1/lib/rails/rack/logger.rb:37:in `call_app'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/railties-6.0.3.1/lib/rails/rack/logger.rb:28:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/sprockets-rails-3.2.1/lib/sprockets/rails/quiet_assets.rb:13:in `call'
 470d0b0b | /usr/share/foreman/lib/foreman/middleware/logging_context_request.rb:11:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/request_id.rb:27:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/method_override.rb:24:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/runtime.rb:22:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/activesupport-6.0.3.1/lib/active_support/cache/strategy/local_cache_middleware.rb:29:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/executor.rb:14:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/static.rb:126:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/sendfile.rb:110:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/actionpack-6.0.3.1/lib/action_dispatch/middleware/host_authorization.rb:76:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/secure_headers-6.3.0/lib/secure_headers/middleware.rb:11:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/railties-6.0.3.1/lib/rails/engine.rb:527:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/railties-6.0.3.1/lib/rails/railtie.rb:190:in `public_send'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/railties-6.0.3.1/lib/rails/railtie.rb:190:in `method_missing'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/urlmap.rb:74:in `block in call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/urlmap.rb:58:in `each'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/rack-2.2.3/lib/rack/urlmap.rb:58:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/puma-4.3.3/lib/puma/configuration.rb:228:in `call'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/puma-4.3.3/lib/puma/server.rb:682:in `handle_request'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/puma-4.3.3/lib/puma/server.rb:472:in `process_client'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/puma-4.3.3/lib/puma/server.rb:328:in `block in run'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/puma-4.3.3/lib/puma/thread_pool.rb:134:in `block in spawn_thread'
 470d0b0b | /opt/theforeman/tfm/root/usr/share/gems/gems/logging-2.2.2/lib/logging/diagnostic_context.rb:474:in `block in create_with_logging_context'
2020-12-17T12:01:26 [I|app|470d0b0b]   Rendering common/500.html.erb
2020-12-17T12:01:26 [I|app|470d0b0b]   Rendered common/500.html.erb (Duration: 2.5ms | Allocations: 837)
2020-12-17T12:01:26 [I|app|470d0b0b] Completed 500 Internal Server Error in 178ms (Views: 4.0ms | ActiveRecord: 26.6ms | Allocations: 30945)

Foreman version: 2.2.2
Plugins: 
 - foreman-tasks 3.0.1
 - foreman_dhcp_browser 0.0.8
 - foreman_discovery 16.2.0
 - foreman_remote_execution 4.1.0

Those services are really running.

root@theforeman ~ # lsof -n -P -i :8443
COMMAND PID          USER   FD   TYPE    DEVICE SIZE/OFF NODE NAME
ruby    348 foreman-proxy   16u  IPv4 788106011      0t0  TCP *:8443 (LISTEN)
ruby    348 foreman-proxy   17u  IPv6 788106012      0t0  TCP *:8443 (LISTEN)
root@theforeman ~ # lsof -n -P -i :8000
COMMAND PID          USER   FD   TYPE    DEVICE SIZE/OFF NODE NAME
ruby    348 foreman-proxy   11u  IPv4 788105094      0t0  TCP *:8000 (LISTEN)
ruby    348 foreman-proxy   13u  IPv6 788105095      0t0  TCP *:8000 (LISTEN)

The output from the smart-proxy services page:

DHCP
Version
2.2.2
Subnets
10_OFFICE (10.10.8.0/22), 20_VOICE (10.10.20.0/24), 110_DMZ (10.10.110.0/24), vlan150_DMZ_Entwicklung (172.16.4.0/24), 401_IRONBIRD (172.16.6.0/24), and VLAN11 (192.168.168.0/24)
DNS
Version
2.2.2
Domains
example.com
Discovery
Version
1.0.5
Dynflow
Version
0.2.4
HTTPBoot
Version
2.2.2
Realm
Version
2.2.2
Realms
EXAMPLE.COM
SSH
Version
0.3.0
TFTP
Version
2.2.2
TFTP server
10.10.8.6