Dear aboee!
You can try it first by following these steps:
In the navigation tree on the left, choose Security > WAN Access Control Configuration . In the pane on the right, click New. In the dialog box that is displayed, set the parameters of the WAN access control, as shown in following figure. Then click apply.

Please note:
Complete network security planning before enabling remote access control to ensure that ONTs are logged in to insecure network conditions. After the ONT login operations are complete, disable remote access control in a timely manner. If you do not complete network security planning or do not disable remote access control in a timely manner, the network may become faulty or be attacked, and Huawei will not be responsible for any related subsequences
If the operation is unsuccessful, please contact your ISP because the function may be restricted.
Good luck!