nginx-proxy-manager/backend/templates/_location.conf

  location {{ path }} {
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-Scheme $scheme;
    proxy_set_header X-Forwarded-Proto  $scheme;
    proxy_set_header X-Forwarded-For    $remote_addr;
    proxy_pass       {{ forward_scheme }}://{{ forward_host }}:{{ forward_port }}{{ forward_path }};
    {{ advanced_config }}
  }