SSH timeout to a campus server while the internet works: check the VPN before you debug SSH

If ssh host fails with 'connect ... port 22: Operation timed out' but general HTTPS works, the cause is usually the network path, not SSH keys or quoting. University and lab servers often accept port 22 only from the campus network or the campus VPN. Do a quick check with nc -vz -G 10 <host> 22. Look at the VPN state on macOS with scutil --nc list. A timeout (not 'connection refused' and not 'permission denied') points to a firewall or VPN problem. Ask the user to connect the VPN instead of changing network settings yourself.