My phone is rebooting on its own again and again

Hello. I got my Moto G4 Plus screen replaced a few days ago. After replacing the screen the phone reboots automatically. First the screen goes blank(whole screen turns black) for a second and again backs to normal or sometimes the header and footer region of the screen goes blank and center part is normal. This happens 3-4 times before the phone reboots. And this reboot cycle continues. While flashing ROM I was in Fastboot mode as well as I was in Recovery mode for more than Half hour but this reboot issue never happened there. I dont know what could be the region. The phone was kept untouched for more than a year before replacing the screen and this never happened before. I thought this could be software issue so I flashed a fresh ROM but all in vain. This is happening in both Stock and Custom ROM. Please help. Thank you,