For example, synapse-admin connects to additional networks here: c0559870b5/roles/custom/matrix-synapse-admin/templates/systemd/matrix-synapse-admin.service.j2 (L39-L41) This defaults to 'traefik' through matrix_playbook_reverse_proxy_container_network, which is not correct in case matrix_playbook_reverse_proxy_type is set to none.
c0559870b5/roles/custom/matrix-synapse-admin/templates/systemd/matrix-synapse-admin.service.j2 (L39-L41)