Hello, friend!
The default user name and password cannot be used to create configurations.
If to configure a WAN, You need to log in to the WebUI of the device using a higher-level user name and password.
For details about the login account and password of Huawei ONTs, click:
Huawei ONT login account and password
Log in to the device WebUI using the administrator account and password.
In the navigation tree on the left, choose Advanced Configuration > WAN Configuration. In the pane on the right, click New.
Note: If you are a home network, contact the ISP and configure the ONT on the OLT.
Thanks!