There are 2 passwords on the back of the router, one for router settings Admin, and one for WiFi.
Have you selected the correct one as you mention settings and won't accept WiFi password?
If you are certain you are trying the correct password for the tight application, then try a pinhole reset of the router. The pinhole can be found on the back of the router and it will restart after a few seconds and put ever6back to it's factory values including passwords.
Let us know how you get on.
Please remember to mark Solved Posts with Best Answer. Doing so helps other customers and saves TalkTalk's Support Team time by only looking at unsolved topics. Thanks, Steve (a fellow customer).
