Gateway not showing up in my ATT support page nor in the App

Hi,

    I have the new Fiber service in my house, and as part of that got the modem Humax BGW320-500. Problem is, I cannot do any typical troubleshooting process with it, like remotely restart, or check it via the app. Att portal sees the modem as "offline".

    The service works. But, I want to make sure I can remotely restart and check it from the Att portal.

    Is there anything I can do on my side? I have the impression this is something to be done from Att side.