Hi.
The modem behaves abnormally. In general, the ADSL light should be static on after you plug the ADSL line into the modem. And LAN leds will be off you do not plug Lan cables into the modem.
In your case, you can reset the modem in this way and see what happens.
1. Press and hold the reset button on the rear panel with a pin, while holding down the reset button restart the router (power off and power on the unit), and please continue holding down the reset button for approximately 15 seconds.
2. Release the reset button and wait for the device to reboot.

After that, if still the same, I'm afraid that it is broken.