Why does my phone shut off while starting up?

While using my phone, its screen went blank.The battery life was at 78%. I attempted to power up the phone. It seemed to be restarting but after about five seconds in the startup screen ("BLU BOLD like US"), the screen went blank again. After removing the phone battery several times, also charging over night, I experience the same issue. (Note: while the phone charges the battery life is visible)