Steinberg UR22mkII doesn't power up with micro USB

Hi, I have the Steinberg UR22mkII audio interface. It is new but I see that it doesn’t up power up when I choose the 5V DC as the power source (micro USB port in the audio interface is connected to 5V adapter that I generally use to charge my iphone). But when I choose the power source as USB 2.0 it powers up. Can some one help on this?

Most likley the phone charger does not supply enough current.

Thanks. I will check with a higher amp phone charger