I baught the 4s and had it activated last night. The battery ran low so I plugged it in. It showed it was charging so I put it down and went to sleep. I woke up this morning with 20%. So I unplugged the dock and plugged it into another outlet, it showed it was charging but after a couple seconds it stoped. I tried this again with a few outlets until plugging it into my computer... it's charging on my computer now, but why wont it charge on the outlet dock?