Cannot access admin GUI or SSH

You can try to start the services from command line or view their status:

systemctl start httpd-admin sshd
systemctl -l status httpd-admin sshd

It’s possible that some errors were logged in /var/log/messages, they could provide some clues about the cause.

Edit: I’m assuming you have NethServer 7.4

Another option, if services are already started but not responding, is to restart them.