Beagle bone black issue

Hi everyone,
a week back purchased beagle bone black from, Board is working fine with USB, But maybe because of insufficient current its getting restarted, again and again, So I decided to gave External power supply with 5v to board After that PMIC is getting shut down, power led will blink for some millisec and turned off. Now it’s not working with USB as well, Please anybody help to resolve this or please guide me on how to do RMA to be done for this.

Use with 5V and 2Amp adapter to power.