Hi @David Holloway ,
Connection timed out means that your VM is not reachable, so there can be several problems:
Have you checked if the public IP has changed because of a reboot of the machine (dynamic public ip)?
Have you checked if a NSG is blocking the SSH Access from the Internet to your machine?
Have you configured the software firewall of the VM (iptables) ?
Are other services on your VM reachable?
Greetings