What brand of TV? Is the box directly connected to the TV through HDMI? When you pair an X1 remote, it will typically ask if you want to program it for the TV too.
Have you paired the remote with your set top box? What make and model of tv do you have? Which remote do you have? You can go to https://www.xfinity.com/support/remotes for self service programming and pairing of remotes. Additionally, if none of the codes work your tv/device may not be supported yet by xfinity's remote.