diff --git a/homeassistant/components/cert_expiry/.translations/en.json b/homeassistant/components/cert_expiry/.translations/en.json
index b6aa1cefb02..85575df6291 100644
--- a/homeassistant/components/cert_expiry/.translations/en.json
+++ b/homeassistant/components/cert_expiry/.translations/en.json
@@ -21,4 +21,4 @@
         },
         "title": "Certificate Expiry"
     }
-}
\ No newline at end of file
+}
diff --git a/homeassistant/components/cert_expiry/__init__.py b/homeassistant/components/cert_expiry/__init__.py
index ab68d5ba08b..7c7efea7333 100644
--- a/homeassistant/components/cert_expiry/__init__.py
+++ b/homeassistant/components/cert_expiry/__init__.py
@@ -1,7 +1,5 @@
 """The cert_expiry component."""
 from homeassistant.config_entries import ConfigEntry
-from homeassistant.const import EVENT_HOMEASSISTANT_START
-from homeassistant.core import callback
 from homeassistant.helpers.typing import HomeAssistantType
 
 
@@ -13,13 +11,7 @@ async def async_setup(hass, config):
 async def async_setup_entry(hass: HomeAssistantType, entry: ConfigEntry):
     """Load the saved entities."""
 
-    @callback
-    def async_start(_):
-        """Load the entry after the start event."""
-        hass.async_create_task(
-            hass.config_entries.async_forward_entry_setup(entry, "sensor")
-        )
-
-    hass.bus.async_listen_once(EVENT_HOMEASSISTANT_START, async_start)
-
+    hass.async_create_task(
+        hass.config_entries.async_forward_entry_setup(entry, "sensor")
+    )
     return True
diff --git a/homeassistant/components/cert_expiry/config_flow.py b/homeassistant/components/cert_expiry/config_flow.py
index dd3463fff95..d73762ce882 100644
--- a/homeassistant/components/cert_expiry/config_flow.py
+++ b/homeassistant/components/cert_expiry/config_flow.py
@@ -38,10 +38,12 @@ class CertexpiryConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
             return True
         return False
 
-    def _test_connection(self, user_input=None):
+    async def _test_connection(self, user_input=None):
         """Test connection to the server and try to get the certtificate."""
         try:
-            get_cert(user_input[CONF_HOST], user_input.get(CONF_PORT, DEFAULT_PORT))
+            await self.hass.async_add_executor_job(
+                get_cert, user_input[CONF_HOST], user_input.get(CONF_PORT, DEFAULT_PORT)
+            )
             return True
         except socket.gaierror:
             self._errors[CONF_HOST] = "resolve_failed"
@@ -59,7 +61,7 @@ class CertexpiryConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
             if self._prt_in_configuration_exists(user_input):
                 self._errors[CONF_HOST] = "host_port_exists"
             else:
-                if self._test_connection(user_input):
+                if await self._test_connection(user_input):
                     host = user_input[CONF_HOST]
                     name = slugify(user_input.get(CONF_NAME, DEFAULT_NAME))
                     prt = user_input.get(CONF_PORT, DEFAULT_PORT)
diff --git a/homeassistant/components/cert_expiry/sensor.py b/homeassistant/components/cert_expiry/sensor.py
index fccfb295c0f..b564cff7338 100644
--- a/homeassistant/components/cert_expiry/sensor.py
+++ b/homeassistant/components/cert_expiry/sensor.py
@@ -9,7 +9,12 @@ import voluptuous as vol
 import homeassistant.helpers.config_validation as cv
 from homeassistant.config_entries import SOURCE_IMPORT
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-from homeassistant.const import CONF_NAME, CONF_HOST, CONF_PORT
+from homeassistant.const import (
+    CONF_NAME,
+    CONF_HOST,
+    CONF_PORT,
+    EVENT_HOMEASSISTANT_START,
+)
 from homeassistant.helpers.entity import Entity
 
 from .const import DOMAIN, DEFAULT_NAME, DEFAULT_PORT
@@ -82,6 +87,15 @@ class SSLCertificate(Entity):
         """Icon to use in the frontend, if any."""
         return self._available
 
+    async def async_added_to_hass(self):
+        """Once the entity is added we should update to get the initial data loaded."""
+
+        def do_update(_):
+            """Run the update method when the start event was fired."""
+            self.update()
+
+        self.hass.bus.async_listen_once(EVENT_HOMEASSISTANT_START, do_update)
+
     def update(self):
         """Fetch the certificate information."""
         try:
diff --git a/tests/components/cert_expiry/test_config_flow.py b/tests/components/cert_expiry/test_config_flow.py
index f8c99496a56..f44e65512e3 100644
--- a/tests/components/cert_expiry/test_config_flow.py
+++ b/tests/components/cert_expiry/test_config_flow.py
@@ -8,7 +8,7 @@ from homeassistant.components.cert_expiry import config_flow
 from homeassistant.components.cert_expiry.const import DEFAULT_PORT
 from homeassistant.const import CONF_PORT, CONF_NAME, CONF_HOST
 
-from tests.common import MockConfigEntry
+from tests.common import MockConfigEntry, mock_coro
 
 NAME = "Cert Expiry test 1 2 3"
 PORT = 443
@@ -20,7 +20,7 @@ def mock_controller():
     """Mock a successfull _prt_in_configuration_exists."""
     with patch(
         "homeassistant.components.cert_expiry.config_flow.CertexpiryConfigFlow._test_connection",
-        return_value=True,
+        side_effect=lambda *_: mock_coro(True),
     ):
         yield