Hello,

If you dont care about the configuration you can do hard reset. The normal hard reset is in the power-on state. Hold down the RESET button for a long period of time (longer than 10s) to restart the ONT with factory settings.

Additional information can be found here:

HOW TO RECOVER LOGIN IP ADDRESS OF ONU HUAWEI HG8546M IF CHANGED

Can't login to the admin panel on a HG8546M

Hello, 

Please press the “Rest” button for 10 to 15 seconds with the thimble in the power on state.

Then log in with the initial password and username. The initial username and password are displayed on the nameplate on the back of the device.

Note:
Please use the factory reset function carefully, which may result in the device not being able to access the Internet.

Thanks

Hello, friend!

For details about how to log in to Huawei ONTs, click

How to login Huawei EchoLife ONT

If you can, provide the version of the HG8546M for you to check whether the HG8546M is customized for the ISP.

Generally, if you forget the login password, you can log in to the device in either of the following ways

1. Press and hold the reset button for 10 seconds to reset the device. After restoring the device to its factory settings, you can use the account and password on the device nameplate to log in to the device. However, the previous configuration data will be lost after the device is reset. In this case, contact the ISP to restore the configuration data.

2. You can obtain the administrator account and password from the ISP to log in to the device WebUI. After logging in to the device WebUI, click the System Tools tab and then choose Modify Login Password from the navigation tree. 

Thanks!