diff --git a/hassio/api/proxy.py b/hassio/api/proxy.py
index 27a6c7cfc..f3ddf4b92 100644
--- a/hassio/api/proxy.py
+++ b/hassio/api/proxy.py
@@ -4,7 +4,7 @@ import logging
 
 import aiohttp
 from aiohttp import web
-from aiohttp.web_exceptions import HTTPBadGateway
+from aiohttp.web_exceptions import HTTPBadGateway, HTTPInternalServerError
 from aiohttp.hdrs import CONTENT_TYPE
 import async_timeout
 
@@ -133,15 +133,19 @@ class APIProxy(CoreSysAttributes):
         await server.prepare(request)
 
         # handle authentication
-        await server.send_json({
-            'type': 'auth_required',
-            'ha_version': self._homeassistant.version,
-        })
-        await server.receive_json()  # get internal token
-        await server.send_json({
-            'type': 'auth_ok',
-            'ha_version': self._homeassistant.version,
-        })
+        try:
+            await server.send_json({
+                'type': 'auth_required',
+                'ha_version': self._homeassistant.version,
+            })
+            await server.receive_json()  # get internal token
+            await server.send_json({
+                'type': 'auth_ok',
+                'ha_version': self._homeassistant.version,
+            })
+        except RuntimeError as err:
+            _LOGGER.error("Can't initialize handshake: %s", err)
+            raise HTTPInternalServerError() from None
 
         # init connection to hass
         client = await self._websocket_client()