Hello, friend!
According to the problem description, the possible causes are as follows:
The ONT hardware is faulty.
The port on the GPON board does not work properly.
The system data is incorrectly configured. As a result, the maximum registration distance of the ONT is set to a small value.
1. Replace the device and check whether the fault is caused by hardware.
2. There are ONTs connected to the PON port that can be registered normally and the ONTs work stably. Therefore, the GPON board is not faulty.
3. Check the physical distance between the ONT that cannot be registered and the OLT. Run the display port info command to check the maximum registration distance of the PON port. If the maximum registration distance of the PON port is too small, run the port range command to change the maximum registration distance of the PON port.
Thanks!