To me it looks like you've connected the power backwards.
If the green clips are input power and the unconnected lead is where you're measuring the voltage (and I'm assuming this, since there's no additional information in the question), then you've connected input voltage to the output of the regulator.
Next, how is your power supply set up? Normally the current rating is the maximum current that can be supplied and the voltage rating is the voltage that should be supplied, so if you have 12 V 2 A power supply, that means that it can supply up to 2 A when running at 12 V. It does not mean that it is actually supplying 2 A all the time.
The regulator is rated for currents up to 1.5 A, but again that doesn't mean that it's providing 1.5 A of current. It only means that if it's cooled correctly, it can tolerate output current as large as 1.5 A, so everything should work fine on that side.