Lost TV Signal

I have ATT UVerse cable TV and internet. My internet is working, but not TV.

The TV signal will only stay on for about 10 sec, then the picture freezed, and gave lost signal message. When I switched to different channel, the TV signal starts again for about 10 sec, then lost again.

I even reboot the TV receiver and Gateway, it still doesn't work.

Can anyone help?

Lan