TV won't shut off

Your Uverse remote must turn off two devices separately: the STB and the TV.  Make sure the "ATT" button on the remote is lighting up when attempting this.  If the "TV" button is lighting up, press the "ATT" button and try again.

Also, give the remote a chance to accomplish both tasks.  If you move the remote away too quickly, you're not allowing enough time to turn off the STB first and the TV second (or vice versa).

@Davids496 - Skeeter has two good suggestions. Another possibility is that while connecting as you described, you left something in front of thee IR sensor on the TV. Make sure it is clear to see the signal from the remote.