SSL connection with dyn ok, but could not connect with internal ip

Hi!
I can connect to my home assistant from my external SSL connection “https://xxx.spdns.de”.

But when I try to connect with my internal IP “https://192.168.178.15:8123” the login site appears, then I enter the correct password. The result is: “Unable to connect

My routing settings:
443:8123

I’m using HassIO with the Let’s Encrypt addon.

Is it not possible to connect with the internal ip?

Thank you