Sometimes when you run a “sudo reboot now” a couple of processes can get stuck and cause the system to hang. It’s usually worth creating a new SSH connection before you start the boot and connect to the server. If the first reboot fails, run this in the second connection:
echo 1 > /proc/sys/kernel/sysrq echo b > /proc/sysrq-trigger
This will tell the system to perform an immediate reboot without running through the normal shutdown sequeneces.