Chromecast integration stopped working

I turned on debug logging for pertinent things and found this:

2020-08-12 22:06:15 DEBUG (MainThread) [homeassistant.components.cast.media_player] Failed to setup chromecast
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/cast/media_player.py", line 200, in _async_setup_platform
    ChromeCastZeroconf.set_zeroconf(await zeroconf.async_get_instance(hass))
  File "/usr/src/homeassistant/homeassistant/helpers/singleton.py", line 31, in wrapped
    result = await func(hass)
  File "/usr/src/homeassistant/homeassistant/components/zeroconf/__init__.py", line 73, in async_get_instance
    return await hass.async_add_executor_job(_get_instance, hass)
  File "/usr/local/lib/python3.8/concurrent/futures/thread.py", line 57, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/src/homeassistant/homeassistant/components/zeroconf/__init__.py", line 86, in _get_instance
    zeroconf = HaZeroconf(**zc_args)
  File "/usr/local/lib/python3.8/site-packages/zeroconf/__init__.py", line 2323, in __init__
    self._listen_socket, self._respond_sockets = create_sockets(
  File "/usr/local/lib/python3.8/site-packages/zeroconf/__init__.py", line 2248, in create_sockets
    respond_socket = add_multicast_member(cast(socket.socket, listen_socket), i, apple_p2p=apple_p2p)
  File "/usr/local/lib/python3.8/site-packages/zeroconf/__init__.py", line 2193, in add_multicast_member
    listen_socket.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, _value)
OSError: [Errno 105] No buffer space available

What would cause this, and how can I fix it?

I took a wild stab and used docker network prune to clean up something like 6 docker-created networks, restarted the home assistant container, and it started working again. There must be a hard limit to the number of multicast members.

[Edited title since this actually had nothing to do with v0.114.0]