Welcome to TPG Community!
We have located the account using your community details. As per checking, your modem is getting line signal, but it is trying to connect to our server with an incorrect username and password.
You will need to access the settings of your modem and configure it with your TPG username and password.
Let us know should you need further assistance.
Can you try to clear the browsing history, try different browser or try a different device?
Can you also provide us the make and model of your modem?
Please make sure that your device is connected to the Wi-Fi network of your modem.
We are not sure if what is the default gateway of your modem, but you may check it on your devices.
If Windows OS, search for CMD then type "ipconfig' and it will display the IP address of your computer and the default gateway (Modem IP address).
Use thew DG to access the modem interface.