Error trying to install ISP3 on ubuntu 20.04 using the perfect server guide for ubuntu 20.04

Yeah I noticed that now, the repo is reachable by the server (I can ping or wget any file in there with no problem) but those repos don't have arm64 only i386 and amd64, so I guess the script like @till said is just replacing the architecture. If I noticed that before I probably would have not come here to bother you guys.

http://security.ubuntu.com/ubuntu/dists/focal/

 

For ubuntu 20.04 arm64 the repos are here:
http://ports.ubuntu.com/ubuntu-ports/dists/focal/
Although not all the packages from ISPconfig are there, SSH is (it can associate the ssh with openssh-server or client don't know which one is actually the ssh package that is ISPconfig is trying to install, I assume is client but for example can't find vim-nox in any repo, but the package officially exists for arm64, just need to install it and all of its dependencies manually in order to work.
https://packages.ubuntu.com/focal/vim-nox

 

manual install on arm should be fine. some packages will be missing, or have alternate names, a quick apt search for the main package, eg ssh, vim, imagick etc should provide you with the alternative name to install.

if installing on arm, always use the system default for mysql / mariadb. *do not* try to add the mariadb repo and use the latest version.
a security update, or normal apt update will end up trying to overwrite it with the system default version, the binaries will get removed, and the update *will not* install, and apt remove / apt purge etc will not allow you to then re-install cleanly. you're in for a world of pain trying to resolve dependency issues and get databases working again.