Hello, it seems is working now but I don't know the reason.
I had latest version when created post. I reset using GUI and reset button lot of times without result.
With latest version, commands about modem not working:
Also tried again the result, no result.
Then, I downgrade to RUTX_R_00.07.00_WEBUI version (the next versions tried this morning).
No result. I was trying bootloader mode to update to latest version. Tried 10 times to connect to bootloader mode but lights flash only 1 seconds. Impossible to conect to WebUI to update firmware even with static IP.
After that, I tried unplug and plug the power to enter normal mode and then suddenly is working.
Updated firmware to latest version via WebUI (modem was in the latest version) and it seems it's working now... will check after next reboots if still working...