diff --git a/homeassistant/components/kef/media_player.py b/homeassistant/components/kef/media_player.py
index f32f825acc4..c1c83f81b36 100644
--- a/homeassistant/components/kef/media_player.py
+++ b/homeassistant/components/kef/media_player.py
@@ -32,6 +32,7 @@ from homeassistant.const import (
     STATE_OFF,
     STATE_ON,
 )
+from homeassistant.exceptions import PlatformNotReady
 from homeassistant.helpers import config_validation as cv, entity_platform
 from homeassistant.helpers.event import async_track_time_interval
 
@@ -123,7 +124,10 @@ async def async_setup_platform(hass, config, async_add_entities, discovery_info=
 
     mode = get_ip_mode(host)
     mac = await hass.async_add_executor_job(partial(get_mac_address, **{mode: host}))
-    unique_id = f"kef-{mac}" if mac is not None else None
+    if mac is None:
+        raise PlatformNotReady("Cannot get the ip address of kef speaker.")
+
+    unique_id = f"kef-{mac}"
 
     media_player = KefMediaPlayer(
         name,