Q:

Ubuntu Core Not Booting on Pi 2 Model B

I bought a brand new RBPi 2 (Model B) Starter Kit that includes a power adapter, cable and 16GB SD card.
I want to install Ubuntu Core which I have followed their tutorial exactly using Mac but the Pi doesn't boot.
The OS is installed on the SD Card perfectly fine (as according to the tutorial) but when I plug the power in then after about 30 secs I go into like a boot-loop. WATCH VIDEO
Just loads up the logo and a list of setup functions but then 'bombs' out and repeats. Looked around on the internet but nothing seems to resolve this issue.

What I've tried:

Tried installing Raspbian but the situation is worse
(just shows RSPi logo then 'bombs' out)
Tried other cables and power adaptors (inc. iPhone and Android plugs) but produce same results.

An idea is that maybe the voltage is too low? Im unable to check the voltage as I currently don't have one but its plugged into the mains with the power adapter and cable it came with; Wouldn't that already be enough power?
I am completely new to this so apologies. Any help is appreciated.

A:

In the official documentation you have some specifications about the required power.
For checking the voltage, check to the red led of the raspberry. It must not blink when booting. If you see that the red led blinks sometimes, that means that your voltage is not correct and you must use a different the adapter. 
Also, I recommend to check the adapter. Not all of them generates enough amperage (specially if you are using a recycled adapter from an old mobile phone)
Also in this raspberry that has bad power supply (where I have installed OSMC), if I have the TV started and connected to the HDMI of the raspberry, the green led freezes and the raspberry does not start. I need to start first the raspberry and later the TV. Otherwise the video test freeze my raspberry. I almost sure that this case is due to an insufficient power supply.

