Dear friend!
Please contact your carrier to check whether the OLT configurations are correct.
Then check whether the WAN port data is mapped to the LAN port and SSID port.
The normal configuration is as follows:
Take the HG8145V5 as an example.
1. Logging In to the device web page
2. In the navigation tree on the left, choose Advanced > WAN. In the pane on the right, click New. In the dialog box that is displayed, set WAN Mode to Route WAN. Then click Apply.

3. In the navigation tree on the left, choose Advanced > LAN > LAN Host. In the pane on the right, set the management IP address of primmary address and secondary address. Then click Apply.

4. In the navigation tree on the left, choose Advanced > LAN > DHCP Server. In the pane on the right, you can configure the LAN side DHCP address pool for the ONT that functions as a gateway. After the configuration, the PC connected to the LAN port can automatically obtain an IP address from the address pool. Then click Apply.

Thanks!