Maybe the X1 box is defective, although you said even the DTA's didn't work. Not sure if you said you hooked the DTA to the only connection right after the grounding block. Could it be a possibility the account isn't turned on for TV service since you said you just had it activated? Maybe you should ask Comcast to check your account and refresh you entitlements. Not sure if ComcastAndrew did that for you already though.
Also check your account online if you have TV service and the equipment matches: https://customer.xfinity.com/MyServices/Video