I am able to boot my Raspberry Pi 2 while using a 1A power supply. However, when I try to power my RP2 with a 2.5A or 3A supply, nothing happens - No LEDs light up and I am unable to measure any voltage between micro USB pin 1 (VCC) and ground. The 2.5A and 3A power supplies work great for charging my cell phone/chromebook, so I am pretty sure there is nothing wrong with them. Also, the 2.5A is brand new and supposed to be compatible with the RP2 (http://www.canakit.com/raspberry-pi-adapter-power-supply-2-5a.html).
What is the problem? Am I missing something completely obvious?
UPDATE: The 2.5A power supply successfully powers a friend's RP2