Why doesn't my PS3 Controller Pair?

I had my PS3 controller disassembled so I could clean it. Once I had it cleaned and reassembled, I went to power it on and I could not get it to power on with the Sony button.

I powered it on by plugging it into my PS3. It turned on with four blinking lights, but after ~15 minutes it never paired with the PS3. I disassembled it and clicked the reset button and re-seated the battery, but these didn’t make a difference.

Any clue as to what may be causing the issue? This controller was working perfectly before I disassembled it.