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

  location {{ path }} {
    {{ advanced_config }}

    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_set_header X-Real-IP		$remote_addr;
    proxy_pass       {{ forward_scheme }}://{{ forward_host }}:{{ forward_port }}{{ forward_path }};

    {% include "_access.conf" %}
    {% include "_assets.conf" %}
    {% include "_exploits.conf" %}
    {% include "_forced_ssl.conf" %}
    {% include "_hsts.conf" %}

    {% if allow_websocket_upgrade == 1 or allow_websocket_upgrade == true %}
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $http_connection;
    proxy_http_version 1.1;
    {% endif %}
  }