ArdexaLinux has a firewall enabled by default that blocks all incoming connections.
The firewall in use is UFW (https://help.ubuntu.com/community/UFW)
To enable a specific port or service, e.g. SSH, run either of the following commands using the Remote Shell. You can use either the service name (if it is a common service such as SSH or HTTP) or the specific port and protocol. Both of these commands achieve the same result.
ufw enable ssh ufw enable 22/tcp
To check the status of the firewall, run
And to disable the service when you are finished
ufw delete allow ssh ufw delete allow 22/tcp