As others have reported, I have long had an error 9003 trying to access the lan settings menu and others.
The error began to manifest itself when I introduced numerous sockets and smart multi-sockets (in total 6 + 1 sonoff).
I tried, as recommended by someone, to set a fixed IP, I updated the firmware. Nothing.
If I unplug 2 or 3 sockets, reboot, it starts to be accessible again.
If I disable the 2.4GHz wifi, reboot, it starts to be accessible again.
A few months ago I also contacted assistance in Italy who promptly replaced me with a "new" modem but suffers from the same problem.

The error worries me because I cannot access the network configuration and client list and I suspect that it may leave some free access to various types of attacks.

I would really like some help with this problem. Thanks

Gianluca