17-02-2020 10:59 PM - edited 17-02-2020 11:01 PM
Have a look on the router label. TalkTalk recent routers have username as admin and a unique router password written on the label. Tip: It's NOT the Wi-Fi name or Wi-Fi password.
If you'd previously changed the router password then factory reset the device using the pinhole reset procedure to reset to the default password on the rear label.