Rest_command cannot connect

HI
I try to send a command to my espeasy as single URLs without using MQTT
I have my rest_command

rest_command:
  vent_off:
    url: "http://ventilation/control?cmd=GPIO,16,1"
    verify_ssl: false

But when i trigger this from an automation i get this error in the log:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/aiohttp/connector.py", line 964, in _create_direct_connection
    hosts = await asyncio.shield(self._resolve_host(
  File "/usr/local/lib/python3.8/site-packages/aiohttp/connector.py", line 829, in _resolve_host
    addrs = await \
  File "/usr/local/lib/python3.8/site-packages/aiohttp/resolver.py", line 29, in resolve
    infos = await self._loop.getaddrinfo(
  File "/usr/local/lib/python3.8/asyncio/base_events.py", line 825, in getaddrinfo
    return await self.run_in_executor(
  File "/usr/local/lib/python3.8/concurrent/futures/thread.py", line 57, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/local/lib/python3.8/socket.py", line 918, in getaddrinfo
    for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
socket.gaierror: [Errno -3] Try again

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/rest_command/__init__.py", line 115, in async_service_handler
    async with getattr(websession, method)(
  File "/usr/local/lib/python3.8/site-packages/aiohttp/client.py", line 1012, in __aenter__
    self._resp = await self._coro
  File "/usr/local/lib/python3.8/site-packages/aiohttp/client.py", line 480, in _request
    conn = await self._connector.connect(
  File "/usr/local/lib/python3.8/site-packages/aiohttp/connector.py", line 523, in connect
    proto = await self._create_connection(req, traces, timeout)
  File "/usr/local/lib/python3.8/site-packages/aiohttp/connector.py", line 858, in _create_connection
    _, proto = await self._create_direct_connection(
  File "/usr/local/lib/python3.8/site-packages/aiohttp/connector.py", line 971, in _create_direct_connection
    raise ClientConnectorError(req.connection_key, exc) from exc
aiohttp.client_exceptions.ClientConnectorError: Cannot connect to host ventilation:80 ssl:default [Try again]

What do i miss? and is it possible to send mutliple urls in same command?
Thanks

My interpretation of the error message is that HA cannot resolve “http://ventilation”… Are you able to connect to that from elsewhere on your machine (i.e. pinging it)? If there is a static IP assigned to that endpoint, have you tried using that instead?

Sorry for late answer. didn’t get any notification.
I’m running Hass.io in hyper-v and when doing a ping from the CLI it says its alive.

Trying with IP works, but this is not suitable.