IAX Modem configuration

I downloaded Nethserver to test its functionality, I would like to activate the fax server using a SIP trunk Asterisk IAX and a modem.
I have created the modem IAX and I set the IP address of the Asterisk server, as internal I typed the username supplied by the provider’s SIP trunk, the password and the geographic number 02xxxxxxxx, I have given a name to the caller and I I entered the email address. I set the modem IAX in sending and receiving mode.
After I configured the Fax Server, I have selected Device standard and Modem IAX in the modem section, so I chose to send notifications to an external e-mail address (providing the address).
I have installed and configured the client software Hylafax (Winprint Hylafax Reloaded).
The client software connects and sends the fax, but it fails and exits the error that the modem is not registered.
From the web control panel there is a function that indicates whether the modem is registered, can I check it from the command line? (On the server it is not cu installed, and with the traditional Hylafax command line is not possible).
Waiting for a reply I greet you cordially.

You should check if a iaxmodem process is running:

ps aux | grep iax

But the best way to check for the extension registration is on the Asterisk side with a command like:

asterisk -rx "iax2 show peers"

@advcorp have you fixed this?