why is my phone boot looping and turning of when unplugged? please help!

[Android Central Question]

hello !
ok so my phone is a galaxy s7 and when i tried to reset to factory form with button combination it just warned me about custom os causing serious damage to the phone and i denied it and now it just loops and shows a blue screen trying to instal updates and shuts itself of after 1 or 2 seconds and if i unplug it the phone is just blank no action from the buttons no lights nothing but if i plug it again starts lopping
no access to recovery or safe mode so please help thank you

 

[B. Diddy]

Welcome to Android Central! It sounds like the phone may have been rooted at some point, with a different firmware installed on it. Assuming you're not the one who did this, can you contact the previous owner? It's possible whatever firmware was installed has become corrupt.