The TV guide info is supplied by your internet connection, how is the 360 connected to your hub ethernet cable or Wi-Fi. If you have any problems using the app's or streaming something then it would point towards a problem there.
If you don't have any problems with the apps then the first thing I would try is rebooting the 360 by turning the power off and on with either the switch on the back of the box or at the plug. You could also try rebooting the hub.
If that doesn't work you could try a factory reset.
It's only a partial system reset and not a complete factory reset. You are given 2 options,
Keep Recordings
Format Disk
Choose Keep Recordings, that means you won't lose your recordings and any planned recordings or series links you've set up, but you will have to sign into your apps such as iPlayer, Prime, Netflix and ITVX again, also Match frame rate and Standby power consumption will go back to their default settings if you have changed them.
