WD MyCloud EX2100 No-Ip WebDAV setup

Hello WD Community,
at the start I want to say sorry for my poor english but please bare with me (and the google translaitor).
I have got a problem with my WD MyCloud EX2100. I want to setup my MyCloud as an Backupserver for a single Computer over the Internet because the Server should be in an other Building. I tryed to use WebDAV with the No-Ip service but I am complitly new to that topic so there are a view errors.
But let’s start at the begining. I think that the MyCloud is ready to go because of this window.

But when I try to connect to the server with CarotDAV i get this error:

I click ignore and then i get this error:
picture 3
(here are all the pictures)
(at this point i am not allowed to use more pictures and links)
My command was this:
picture 4
and I got the login by SQLite with the Orion.db data
picture 5
i tryed the ports 8080 and 4443 in carotdav but there are also errors.
I used a Fritz!Box and i typed this in
picture 6
This is what I have at No-IP:
picture 7
sorry that somethings are in german but I cant turn them in english or i am not allowed to do that.
and sorry for the pictures but I am not allowed to use more pictures in this comunity
I hope you can help me.
Thanks for the help in advance. :smiley:

Hopefully an experienced User will be able to assist.

On the other hand, the following thread discusses similar circumstances even though it’s for a different device. Nonetheless, perhaps it will be able to provide some clues.