You probably need to program you TV. The programming procedure varies from one TV model to the next, but here are some general instructions:

(You can use your TV set’s channel up and down buttons to scroll through the menu and the volume up button to enter if the remote control is unavailable.)

Press the menu button on your TV or remote control.

Select Tuner, First Time Set-Up, Channel Set-Up, Antenna, or Source.

Make sure Cable TV, CAB, or CATV is selected.

Run Autoprogram or Channel Memorize.