Let’s Encrypt re-new and expire sensor did not work

I have a problem with my SSL certificate.
I use Hass.Io and the Lets Encrypt add-on.
First I installed Hass.IO by the instruction from Bruh automation.
I forwarded port 80>80 and 443>443 on my router. Then start the Let’s Encrypt add-on and everything is fine. Then I forwarded 443>8123 and my https connection works! Great!

But I use the sensor.cert_expiry to see how many days left until my certification expires.

- platform: cert_expiry
  host: https://xxx.spdns.de

After I reboot, this message appears in the Log:

(SyncWorker_17) [homeassistant.components.sensor.cert_expiry] Cannot connect to https://xxx.spdns.de

But I can connect to the page!
Is there a bug?

And the instruction of the Let’s Encrypt add-on says if I want to re-new the certificate, I have to change the routing back to 80>80 and 443>443- but how could I connect then through the website to start the let’s Encrypt add-on?

i think the host should be in the xxxxxxx.yyyyyyyy.zzzzzzzzzz format and not https://xxxxxxxxx.yyyyyyyy.zzzzzzzzzz

That’s what I’m doing and mine has been working just fine.

Oh yes! That’s the solution!

i have this but the sensor is showing nothing

 - platform: cert_expiry
    host: my.duckdns.org

Try use the duckdns addon