After doing a Guided Setup it is not uncommon for the clock to be wrong.

Go into TiVoWEB and check the Phone menu. If you have the message that the last call attempt has succeeded and NOT still loading data or indexing shows then reboot the TiVo.

If the clock is still wrong you have problems. In which case first thing is to ensure that your router and/or firewall (whichever is applicable for your network) is not blocking port 37 which is used to adjust the clock.