Unable to setup remote access

I have the problem that I am unable to setup my remote access.

I have a pi with nextcloudpi installed and already used the remote access some years ago. after moving i had no public ipv4. But now i want to setup the remote access again.

I created a new ddns with no-ip. Previously I used freedns but apparently my domain is gone now.

So I created a new one, put my public IP in the domain. Here I have the first question. The public IP is is the same for all devices. How can I map a Device IP to this domain? Or do I have to put the Device IP in?

After that I used the WebUI to put my domain, user name and password in. But now I always get this meassage:

Failed to enable unit: Unit /run/systemd/generator.late/noip2.service is transient or generated.
warning: No domain found. Defaulting to ‘nextcloudpi’

What am I missing? I have the feeling that my old domain might be an issue.

Hi, you’ll need to setup port forwarding.